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Study Question: Do the length of follicular phase estradiol exposure and the total length of the follicular phase affect pregnancy and live birth outcomes in natural frozen embryo transfer (FET) cycles?, Summary Answer: An estradiol level >100 pg/ml for ≤4 days including the LH surge day is associated with worse pregnancy and live birth outcomes; however, the total length of the follicular phase is not associated with pregnancy and live birth outcomes., What Is Known Already: An estradiol level that increases above 100 pg/ml and continues to increase is indicative of the selection and development of a dominant follicle. In programmed FET cycles, a limited duration of follicular phase estradiol of <9 days results in worse pregnancy rates, but a prolonged exposure to follicular phase estradiol for up to 4 weeks does not affect pregnancy outcomes. It is unknown how follicular phase characteristics affect pregnancy outcomes in natural FET cycles., Study Design, Size, Duration: This retrospective cohort study included infertile patients in an academic hospital setting who underwent their first natural frozen autologous Day-5 embryo transfer cycle in our IVF clinic between 01 January 2013 and 31 December 2018. Donor oocyte and gestational carrier cycles were excluded., Participants/materials, Setting, Methods: The primary outcomes of this study were pregnancy and live birth rates. Patients were stratified into two groups based on the cohorts' median number of days from the estradiol level of >100 pg/ml before the LH surge: Group 1 (≤4 days; n = 1052 patients) and Group 2 (>4 days; n = 839 patients). Additionally, patients were stratified into two groups based on the cohorts' median cycle day of LH surge: Group 1 (follicular length ≤15 days; n = 1287 patients) and Group 2 (follicular length >15 days; n = 1071 patients). A subgroup analysis of preimplantation genetic testing for aneuploidies (PGT-A) embryo transfer cycles was performed. Logistic regression analysis, adjusted a priori for patient age, number of embryos transferred, and use of PGT-A, was used to estimate the odds ratio (OR) with a 95% CI., Main Results and the Role of Chance: In the length of elevated estradiol analysis, the pregnancy rate per embryo transfer was statistically significantly lower in patients with an elevated estradiol to surge of ≤4 days (65.6%) compared to patients with an elevated estradiol to surge of >4 days (70.9%; OR 1.30 (95% CI 1.06-1.58)). The live birth rate per embryo transfer was also statistically significantly lower in patients with an elevated estradiol to surge of ≤4 days (46.6%) compared to patients with an elevated estradiol to surge of >4 days (52.0%; OR 1.23 (95% CI 1.02-1.48)). In the follicular phase length analysis, the pregnancy rate per embryo transfer was similar between patients with a follicular length of ≤15 days (65.4%) and patients with a follicular length of >15 days (69.0%; OR 1.12 (95% CI 0.94-1.33)): the live birth rate was also similar between groups (45.5% vs 51.5%, respectively; OR 1.14 (95% CI 0.97-1.35)). In all analyses, once a pregnancy was achieved, the length of the follicular phase or the length of elevated oestradiol >100 pg/ml no longer affected the pregnancy outcomes., Limitations, Reasons for Caution: The retrospective design of this study is subject to possible selection bias in regard to which patients at our clinic were recommended to undergo a natural FET compared to a fresh embryo transfer or programmed FET. To decrease the heterogeneity of our study population, we only included patients who had blastocyst embryo transfers; therefore, it is unknown whether similar results would be observed in patients with cleavage-stage embryo transfers. The retrospective nature of the study design did not allow randomized to a specific ovarian stimulation or ovulation trigger protocol. However, all patients were managed with the standardized protocols at a single center, which strengthens the external validity of our results when compared to a study that only evaluates one specific stimulation protocol., Wider Implications of the Findings: Our observations provide cycle-level characteristics that can be applied during a natural FET cycle to help optimize embryo transfer success rates. Physicians should consider the parameter of number of days that oestradiol is >100 pg/ml prior to the LH surge when determining whether to proceed with embryo transfer in a natural cycle. This cycle-specific characteristic may also help to provide an explanation for some failed transfer cycles. Importantly, our findings should not be used to determine whether to recommend a natural or a programmed FET cycle for a patient, but rather, to identify natural FET cycles that are not optimal to proceed with embryo transfer., Study Funding/competing Interest(s): No financial support, funding, or services were obtained for this study. The authors do not report any potential conflicts of interest., Trial Registration Number: N/A., (© The Author(s) 2021. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Do women ≥40 years old without a male partner who utilize donor sperm have the same reproductive outcomes as those who utilize their partner's sperm?, Summary Answer: After controlling for relevant confounders, women ≥40 years old using donor sperm for IVF have significantly higher odds of having a live birth compared to those utilizing their partner's sperm., What Is Known Already: Women who are unpartnered or in same-sex relationships are by definition not infertile, but may choose to conceive using donor sperm. It is not known how IVF outcomes are affected with the use of donor sperm compared to women utilizing their partner's sperm, particularly at very advanced maternal ages., Study Design, Size, Duration: This is a retrospective cohort study conducted at a university-affiliated center of women undergoing IVF with fresh embryo transfer between 2008 and 2018., Participants/materials, Setting, Methods: Patients were divided into two groups based on the ejaculated sperm source utilized: donor or partner sperm. Live birth rate was the primary outcome. Pregnancy rate was the secondary outcome. Multivariable logistic regression was performed and adjusted for age, the developmental stage of the embryo, and the number of embryos transferred. Unadjusted odds ratio (OR) and adjusted OR (aOR) with 95% CI for pregnancy and live birth were estimated. Statistical significance was denoted by P < 0.05., Main Results and the Role of Chance: A total of 3910 cycles in women ≥40 years old were analyzed, of which 307 utilized donor sperm and 3603 utilized their partner's sperm to conceive. In the univariate analysis, patients utilizing donor sperm were found to have similar pregnancy rates as those utilizing partner sperm (41.0 vs 39.8%, OR: 0.95, 95% CI: 0.75-1.20). After adjusting for age, the number of embryos transferred and the developmental stage of the embryos, the model estimates did not vary (aOR: 1.22, 95% CI: 0.95-1.56). Similarly, the univariate analysis for live birth did not demonstrate a difference between groups (19.2 vs 17.8%, OR: 0.91, 95% CI: 0.67-1.22). However, after a similar adjustment was made for confounders, the use of donor sperm was associated with statistically significant increased odds of live birth (aOR: 1.38, 95% CI: 1.01-1.88)., Limitations, Reasons for Caution: As with any retrospective study, the potential for residual confounding exists, despite attempts to control for this with regression modeling., Wider Implications of the Findings: Women ≥40 years old who are unpartnered or in same-sex relationships can be counseled that their odds of a live birth are slightly better than women in heterosexual relationships utilizing their partner's sperm. These findings serve to further refine and individualize counseling on the expected IVF outcomes for women in this population., Study Funding/competing Interest(s): No funding was sought for this study. The authors declare no competing interests., Trial Registration Number: N/A., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Will a delay in initiating IVF treatment affect pregnancy outcomes in infertile women with diminished ovarian reserve?, Summary Answer: A delay in IVF treatment up to 180 days does not affect the live birth rate for women with diminished ovarian reserve when compared to women who initiate IVF treatment within 90 days of presentation., What Is Known Already: In clinical practice, treatment delays can occur due to medical, logistical or financial reasons. Over a period of years, a gradual decline in ovarian reserve occurs which can result in declining outcomes in response to IVF treatment over time. There is disagreement among reproductive endocrinologists about whether delaying IVF treatment for a few months can negatively affect patient outcomes., Study Design, Size, Duration: A retrospective cohort study of infertile patients in an academic hospital setting with diminished ovarian reserve who started an IVF cycle within 180 days of their initial consultation and underwent an oocyte retrieval with planned fresh embryo transfer between 1 January 2012 and 31 December 2018., Participants/materials, Setting, Methods: Diminished ovarian reserve was defined as an anti-Müllerian hormone (AMH) <1.1 ng/ml. In total, 1790 patients met inclusion criteria (1115 immediate and 675 delayed treatment). Each patient had one included cycle and no subsequent data from additional frozen embryo transfer cycles were included. Since all cycle outcomes evaluated were from fresh embryo transfers, no genetically tested embryos were included. Patients were grouped by whether their cycle started 1-90 days after presentation (immediate) or 91-180 days (delayed). The primary outcome was live birth (≥24 weeks of gestation). A subgroup analysis of more severe forms of diminished ovarian reserve was performed to evaluate outcomes for patients with an AMH <0.5 and for patients >40 years old with an AMH <1.1 ng/ml (Bologna criteria for diminished ovarian reserve). Logistic regression analysis, adjusted a priori for patient age, was used to estimate the odds ratio (OR) with a 95% CI. All pregnancy outcomes were additionally adjusted for the number of embryos transferred., Main Results and the Role of Chance: The mean ± SD number of days from presentation to IVF start was 50.5 ± 21.9 (immediate) and 128.8 ± 25.9 (delayed). After embryo transfer, the live birth rate was similar between groups (immediate: 23.9%; delayed: 25.6%; OR 1.08, 95% CI 0.85-1.38). Additionally, a similar live birth rate was observed in a subgroup analysis of patients with an AMH <0.5 ng/ml (immediate: 18.8%; delayed: 19.1%; OR 0.99, 95% CI 0.65-1.51) and in patients >40 years old with an AMH <1.1 ng/ml (immediate: 12.3%; delayed: 14.7%; OR 1.21, 95% CI 0.77-1.91)., Limitations, Reasons for Caution: There is the potential for selection bias with regard to the patients who started their IVF cycle within 90 days compared to 91-180 days after initial consultation. In addition, we did not include patients who were seen for initial evaluation but did not progress to IVF treatment with oocyte retrieval; therefore, our results should only be applied to patients with diminished ovarian reserve who complete an IVF cycle. Finally, since we excluded patients who started their IVF cycle greater than 180 days from their first visit, it is not known how such a delay in treatment affects pregnancy outcomes in IVF cycles., Wider Implications of the Findings: A delay in initiating IVF treatment in patients with diminished ovarian reserve up to 180 days from the initial visit does not affect pregnancy outcomes. This observation remains true for patients who are in the high-risk categories for poor response to ovarian stimulation. Providers and patients should be reassured that when a short-term treatment delay is deemed necessary for medical, logistic or financial reasons, treatment outcomes will not be affected., Study Funding/competing Interest(s): No financial support, funding or services were obtained for this study. The authors do not report any potential conflicts of interest., Trial Registration Number: Not applicable., (© The Author(s) 2020. Published by Oxford University Press on behalf of European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Study Question: Does ovarian stimulation affect embryo euploidy rates or live birth rates (LBRs) after transfer of euploid embryos?, Summary Answer: Euploidy rates and LBRs after transfer of euploid embryos are not significantly influenced by gonadotropin dosage, duration of ovarian stimulation, estradiol level, follicle size at ovulation trigger or number of oocytes retrieved, regardless of a woman's age., What Is Known Already: Aneuploidy rates increase steadily with age, reaching >80% in women >42 years old. The goal of ovarian stimulation is to overcome this high aneuploidy rate through the recruitment of several follicles, which increases the likelihood of obtaining a euploid embryo that results in a healthy conceptus. However, several studies have suggested that a high response to stimulation might be embryotoxic and/or increase aneuploidy rates by enhancing abnormal segregation of chromosomes during meiosis. Furthermore, a recent study demonstrated a remarkable difference in euploidy rates, ranging from 39.5 to 82.5%, among young oocyte donors in 42 fertility centres, potentially suggesting an iatrogenic etiology resulting from different stimulation methods., Study Design, Size, Duration: This is a retrospective cohort study that included 2230 in vitro fertilisation (IVF) with preimplantation genetic testing for aneuploidy (PGT-A) cycles and 930 frozen-thawed single euploid embryo transfer (FET) cycles, performed in our centre between 2013 and 2017., Participants/materials, Setting, Methods: A total of 12 298 embryos were analysed for ploidy status. Women were divided into five age groups (<35, 35-37, 38-40, 41-42 and >42 years old). Outcomes were compared between different durations of stimulation (<10, 10-12 and ≥13 days), total gonadotropin dosages (<4000, 4000-6000 and >6000 IU), numbers of oocytes retrieved (<10, 10-19 and ≥20 oocytes), peak estradiol levels (<2000, 2000-3000 and >3000 pg/mL), and sizes of the largest follicle on the day of trigger (<20 and ≥20 mm)., Main Results and the Role of Chance: Within the same age group, both euploidy rates and LBRs were comparable between cycles regardless of their differences in total gonadotropin dosage, duration of stimulation, number of oocytes harvested, size of the largest follicles or peak estradiol levels. In the youngest group, (<35 years, n = 3469 embryos), euploidy rates were comparable between cycles with various total gonadotropin dosages (55.6% for <4000 IU, 52.9% for 4000-6000 IU and 62.3% for >6000 IU; P = 0.3), durations of stimulation (54.4% for <10 days, 55.2% for 10-12 days and 60.9% for >12 days; P = 0.2), number of oocytes harvested (59.4% for <10 oocytes, 55.2% for 10-19 oocytes and 53.4% for ≥20 oocytes; P = 0.2), peak estradiol levels (55.7% for E2 < 2000 pg/mL, 55.4% for E2 2000-3000 pg/mL and 54.8% for E2 > 3000 pg/mL; P = 0.9) and sizes of the largest follicle (55.6% for follicles <20 mm and 55.1% for follicles ≥20 mm; P = 0.8). Similarly, in the oldest group (>42 years, n = 1157 embryos), euploidy rates ranged from 8.7% for gonadotropins <4000 IU to 5.1% for gonadotropins >6000 IU (P = 0.3), from 10.8% for <10 days of stimulation to 8.5% for >12 days of stimulation (P = 0.3), from 7.3% for <10 oocytes to 7.4% for ≥20 oocytes (P = 0.4), from 8.8% for E2 < 2000 pg/mL to 7.5% for E2 > 3000 pg/mL (P = 0.8) and from 8.2% for the largest follicle <20 mm to 8.9% for ≥20 mm (P = 0.7). LBRs after single FET were also comparable between these groups., Limitations, Reasons for Caution: Although this large study (2230 IVF/PGT-A cycles, 12 298 embryos and 930 single FET cycles) demonstrates the safety of ovarian stimulation in terms of aneuploidy and implantation potential of euploid embryos, a multi-centre study may help to prove the generalisability of our single-centre data., Wider Implications of the Findings: These findings reassure providers and patients that gonadotropin dosage, duration of ovarian stimulation, estradiol level, follicle size at ovulation trigger and number of oocytes retrieved, within certain ranges, do not appear to significantly influence euploidy rates or LBRs, regardless of the woman's age., Study Funding/competing Interest(s): No external funding was received and there are no competing interests to declare., Trial Registration Number: N/A., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Study Question: Is there a benefit to assessing ploidy in delayed embryos reaching the morula stage on Day 6 of development?, Summary Answer: Day-6 morulae should be considered for biopsy in women <40 years old undergoing preimplantation genetic testing for aneuploidy (PGT-A) because they are associated with acceptable, albeit reduced, euploidy and implantation rates (IRs)., What Is Known Already: Embryo development and morphology have been shown to correlate with aneuploidy and pregnancy rates. During PGT-A cycles, embryos are biopsied if they reach the blastocyst stage by Day 5 or 6, whereas slow-developing embryos are typically deselected and discarded. Determining the viability of slow-developing embryos is particularly relevant for women undergoing PGT-A who have diminished ovarian reserve and a relatively low blastocyst yield., Study Design, Size, Duration: This is a retrospective cohort study that was performed at an academic medical center. Patients who underwent IVF with PGT-A were reviewed for inclusion., Participants/materials, Setting, Methods: A total of 1615 cycles were reviewed. All cycles which involved a biopsy of a cavitating or compacted morula on Day 6 were included (n = 763). PGT-A was performed using array comparative genomic hybridization. The aneuploidy and implantation of morulae were compared to those of blastocysts originating from the same couples., Main Results and the Role of Chance: The study included 763 cycles in which 1260 morulae and 3014 blastocysts were biopsied. Women were divided into four age groups (<35, 35-37, 38-39 and ≥40 years): the prevalence of aneuploidy was consistently lower among blastocysts (40.3, 50.8, 56 and 78.3%, respectively) than among compacted morulae (68.7, 75.5, 88.9 and 98.1%, respectively) and cavitating morulae (57, 66.4, 81 and 91.6%, respectively) throughout the different age groups (P < 0.001). Of note, the majority of compacted morulae (98.1%) and cavitating morulae (91.6%) were aneuploid in women aged ≥40 years. Compacted and cavitating morulae had significantly higher rates of complex aneuploidy, which involves ≥3 chromosomes, compared with blastocysts (P < 0.001). Furthermore, euploid morulae were associated with a significantly lower IR (28.2 versus 54.6%; P = 0.002) and live birth rate (23.1 versus 55.0%; P = 0.001) compared to euploid blastocysts., Limitations Reasons for Caution: This study confirms that Day-6 morulae should not be discarded in young women undergoing PGT-A. However, a potential drawback of biopsying embryos at the morula stage is the inability to distinguish between inner cell mass and trophectoderm cell origin. The sample size of euploid morula transfer cycles in this study was limited. Thus, a larger cohort would be beneficial to validate the reassuring live birth and spontaneous abortion rates reported here. Furthermore, the reproducibility of our findings should be determined at different centers., Wider Implications of the Findings: Although Day-6 morulae are associated with higher aneuploidy rates and lower IRs compared to blastocysts, they still yielded successful pregnancies. Therefore, testing Day-6 morulae should be considered, especially for women <40 years old who are undergoing PGT-A with a small cohort of available blastocysts for biopsy., Study Funding/competing Interest(s): The authors have nothing to disclose. They received no specific funding for this work., Trial Registration Number: N/A.

Study Question: Is supraphysiologic estradiol (E2) an independent predictor of low birth weight (LBW) in singletons born after fresh IVF-embryo transfer (ET) cycles?, Summary Answer: Our results suggest that E2 > 2500 pg/ml is an independent predictor for LBW in full-term singletons born to normal responder patients undergoing fresh IVF-ET cycles., What Is Known Already: The pathogenesis of LBW in IVF singletons remains unknown. However, recent studies have suggested that the hyperestrogenic milieu generated during ovarian stimulation may create a sub-optimal peri-implantation environment, leading to placental dysfunction, and therefore, LBW., Study Design, Size, Duration: Retrospective cohort study of normal responder patients, <40 years old, undergoing fresh IVF-ET cycles resulting in live singleton births between January 2005 and June 2014., Participants/materials, Setting, Methods: A total of 6419 patients had live births after fresh IVF-ET during the study period, of which 2348 (36.6%) patients were excluded due to multiple gestation, vanishing twins or incomplete records. Perinatal outcomes recorded for all patients included birth weight, gestational age (GA) at delivery, mode of delivery and gender. Term birth, preterm birth (PTB) and LBW incidence proportions were plotted against E2 level on the day of trigger. The term LBW incidence proportion (i.e. singletons born at GA ≥ 37 weeks with birth weight <2500 g) was considered the primary outcome of interest., Main Results and the Role of Chance: A total of 4071 patients with live singleton births were included. The median age, BMI, E2 level and birth weight for the study cohort was 36 (33-39) years, 22.3 (20.4-25.0) kg/m2, 1554 (1112.7-2179) pg/ml and 3289 (2920-3628) g, respectively. The incidence proportion of LBW rose from 6.4% (E2 2001-2500 pg/ml) to 20.7% (E2 3501-4000 pg/ml), without a corresponding rise in the incidence proportion of PTB. The odds of term LBW with E2 > 2500 pg/ml were 6.1-7.9 times higher compared to the referent E2 group. Multivariable logistic regression analysis revealed that E2 was an independent predictor for term LBW, even after adjusting for age, BMI, race, parity, infertility diagnosis, duration of ovarian stimulation, gonadotropin dosage and method of insemination (adjusted odds ratio 10.8, 95% CI 9.2-12.5). Receiver operating characteristic analysis generated an AUC estimate of 0.85 for E2 level as a predictor of LBW., Limitations Reasons for Caution: The current study did not include analyses of hypertensive disorders of pregnancy or placental abnormalities. Furthermore, all patients were normal responders and of normal BMI, possibly limiting the overall generalizability of the study. Finally, as with any retrospective study, prospective data are required to validate the role of E2 in predicting LBW., Wider Implications of the Findings: Our results emphasize the importance of minimizing the supraphysiologic elevations of E2 levels during ovarian stimulation in fresh IVF-ET cycles. This, in turn, can optimize the early peri-implantation environment and mitigate adverse perinatal outcomes such as LBW., Study Funding/competing Interest(s): Dr Paul J. Christos was partially supported by the following grant: Clinical and Translational Science Center at Weill Cornell Medical College (UL1-TR000457-06)., Trial Registration Number: N/A., (© The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com)

Study Question: Do parents with children created through oocyte donation (OD) follow through with their original intentions regarding disclosure to their offspring, and if not, why not?, Summary Answer: Although 43% of this study population had disclosed to their offspring as intended, 39% had delayed disclosure because of uncertainty about how and when to disclose., What Is Known Already: Previous research studies have primarily investigated the intentions of families regarding disclosure to offspring conceived with gamete donation, but have not focused on what actually occurs in the disclosure process., Study Design, Size, Duration: Data from 72 subjects were collected utilizing a 52-item questionnaire developed by the authors from January to May 2012. This cross-sectional hypothesis-generating pilot study utilized descriptive statistics, including frequency and percentiles in order to characterize survey responses., Participants/materials, Setting, Methods: A total of 459 families who delivered a child (or children) after using OD between 1992 and 2003 were invited by mail to participate. The parents were invited to a 1-day, professionally led seminar on issues about oocyte-donation and disclosure. The study, performed at a large university-based fertility clinic, included 72 parents, representing 46 families and 66 children ranging in age from 7 to 19 years., Main Results and the Role of Chance: The findings indicate that 43% of the study population disclosed to their offspring as intended, 39% still intend to disclose, 9% are uncertain and 9% do not plan to disclose at any time. The average age of children at the time of disclosure was 5.5 years. The average age of children at the time of data collection was 13 years. Primary reasons for disclosure were the child's right to know, the desire to be open and honest, and the notion that family secrets are harmful. For families who still intend to disclose, the average age of the offspring was 11 years and primary reasons for delayed disclosure included 'never finding the right time' and uncertainty about how and when to disclose. An unanticipated finding was that delayed disclosure among those who intend to tell offspring resulted in heightened levels of parental anxiety about disclosing to older children. Demographic data showed no associations with disclosure or non-disclosure to offspring. The response rate to participation was 12%., Limitations, Reasons for Caution: Limitations of this study include a low response rate due to potential participants being lost to follow-up and to the possibility that families choosing non-disclosure did not respond to the invitation. This lack of a more effective recruitment strategy may have resulted in the smaller, self-selected study population. Additional limitations included the lack of heterogeneity of our population, any confounding factors the seminars may have had on the choice to participate in the study and on responses to the questionnaire, and the lack of a specified anxiety measurement., Wider Implications of the Findings: Families disclosing to children by the age of 8 reported the lowest levels of conflict regarding the disclosure process and the highest levels of satisfaction at having disclosed early. The findings are consistent with, and add to, a growing body of literature on disclosure in donor-assisted reproduction. The authors recommend that fertility programs and mental health providers better assist OD parents with disclosure issues by recommending early disclosure for those who plan to tell, and by providing on-going follow-up and support to ensure that disclosure decisions are implemented as originally intended., Study Funding/competing Interests: Partial study funding was received from an educational grant from Ferring Pharmaceuticals, Inc. There are no conflicts of interest to declare., (© The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Study Question: Does follicular flushing during oocyte retrieval improve the number of oocytes retrieved in the poorest responders?, Summary Answer: Follicular flushing in the poorest responders does not increase the number of oocytes retrieved and may result in lower implantation and clinical pregnancy rates., What Is Known Already: Although previous studies have shown no beneficial effect of follicular flushing in normal responders, no study has demonstrated a detrimental effect and many IVF centers continue to perform this technique in poor responders. Data on follicular flushing in this patient group are limited, with no randomized trial to date assessing its utility in the poorest responders., Study Design, Size, Duration: This randomized controlled trial compared the effects of follicular flushing and direct aspiration on IVF outcomes in the poorest responders, defined as having four or fewer follicles ≥12 mm on the day of hCG administration. Fifty patients were randomized during the 12-month enrollment period., Participants/materials, Setting, Methods: The patients were treated at an academic fertility center at Weill Cornell Medical College, New York., Main Results and the Role of Chance: Fifty women were randomized to follicular flushing (n = 25) or direct aspiration (n = 25). One patient in the direct aspiration group was canceled prior to oocyte retrieval for premature ovulation and was included in the intent-to-treat analysis. There was no difference in the number of oocytes retrieved with a median (IQR) of 4 (2-6) in the aspiration group versus 3 (2-5) in the flushing group (95% CI: -0.78, 1.98; P = 0.41). Patients who underwent follicular flushing had significantly fewer embryos transferred {1.7 [standard deviation (SD) 0.6] versus 2.5 (SD 1.2), P = 0.03}, a lower implantation rate (5.3 versus 34.2%, P = 0.006) and a lower clinical pregnancy rate (4 versus 36%, P = 0.01). The difference in pregnancy rates remained significant after adjusting for embryos transferred., Limitations, Reasons for Caution: Findings, including results for secondary outcome measures, may not be generalizable to natural IVF cycles as these were excluded from the study., Wider Implications of the Findings: This is the first randomized trial to evaluate the utility of follicular flushing in the poorest responders, and the first to demonstrate a potentially detrimental effect of flushing on IVF outcomes., Study Funding/competing Interest(s): None., Trial Registration Number: NCT 01558141.

Background: The objective of this study is to determine if ultrasound-guided trial transfer (UTT) in the office in preparation for an IVF cycle can be utilized as an alternative and/or adjunct to ultrasound-guided embryo transfer (UGET)., Methods: Patients planning to undergo an IVF cycle at an academic centre were included. Each patient underwent an UTT in the office by the same practitioner. The difference in length (DL), if any, was measured from the perceived top of the uterine cavity (catheter tip) to the actual cavity apex as visualized by ultrasound., Results: Of the 64 patients enrolled, 19 patients (29.7%) had a measurable DL, of which 14 (21.9%) had a DL exists 0.5 cm, and nine (14.1%) had a DL exists 1.0 cm. Significant differences were noted between patients when comparing DL to previous pregnancy status and the total cavity depth (sounding depth + DL) (P < 0.05)., Conclusion: UTT in the office setting appears to be beneficial in preparation for an IVF cycle with embryo transfer.

Background: Studies have suggested that ultrasound-guided embryo transfer (UG-ET) may improve the outcome in IVF; however, several factors may account for the improvement in pregnancy rate. This study examines the use of ultrasound to determine the accuracy of trial transfer (TT) in preparation for ET., Methods: Sixty-seven consecutive patients prospectively underwent UG-ET over a 2 month period. Total cavity length by US was compared with the length noted by TT. A difference of > or = 1 cm was considered significant. All embryos were placed within 1-2 cm of the fundus by US., Results: Twenty patients (29.9%) had a difference of > or = 1 cm and 13 patients (19.4%) had a difference of < or = 1.5 cm. Patients with a difference of > or = 1 or > or = 1.5 cm had a significantly greater depth at transfer (P < 0.001) and uterine cavity length (P < 0.001) when compared with patients without a difference. Clinical pregnancy, implantation, delivery and overall miscarriage rates did not differ between patients with a difference of > or = 1 or > or = 1.5 cm versus no difference. There were no ectopic pregnancies., Conclusions: Nineteen percent of patients had a discrepancy of > or = 1.5 cm and approximately 30% had a difference of > or = 1 cm from TT at UG-ET, suggesting a benefit to UG-ET. A large prospective randomized trial comparing UG-ET with blind transfer is required to assess further if UG-ET should be used in all cases of ET.

Background: This paper is a systematic review of metformin versus clomiphene citrate (CC) in women with polycystic ovary syndrome (PCOS)., Methods: Meta-analysis Of Observational Studies in Epidemiology (MOOSE) and QUality Of Reporting Of Meta-analyses (QUOROM) guidelines were followed. A systematic computerized literature search was done of seven bibliographic databases. Inclusion criteria included cohort and randomized controlled trials (RCT) of women with PCOS and the following medications: metformin versus placebo; metformin versus CC; metformin plus CC versus placebo plus CC. Rev-man 4.1 and Metaview 4.0 were used to analyse data. Relative risk (RR) estimates were presented. A chi2-test determined the significance of the association. Heterogeneity was determined by the Cochran Q-test., Results: Metformin was 50% better than placebo for ovulation induction in infertile PCOS patients [RR 1.50; 95% confidence interval (CI) 1.13, 1.99]. Metformin was also of benefit in non-infertile (i.e. patients with PCOS who were not complaining of infertility) PCOS patients for cycle regulation compared to placebo (RR 1.45; CI 1.11, 1.90). Metformin was not of confirmed benefit versus placebo for achievement of pregnancy (RR 1.07; CI 0.20, 5.74). Metformin plus CC may be 3-4-fold superior to CC alone for ovulation induction (RR 3.04; CI 1.77, 5.24) and pregnancy (RR 3.65; CI 1.11, 11.99) in women with PCOS., Conclusions: Metformin is effective for ovulation induction and cycle regulation in this group of patients. Metformin plus CC appears to be very effective for achievement of pregnancy compared to CC alone. No RCTs directly compare metformin to CC but the need for such a trial exists.

Background: Elevated maternal serum levels of interleukin-2 soluble receptor-alpha (IL-2 sRalpha), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) have been associated with pregnancy loss. The aim of our study was to evaluate the predictive value of these cytokines in the outcome of early IVF pregnancies., Methods: One hundred and fifty-nine consecutive IVF patients who were subsequently diagnosed to have a biochemical pregnancy (n = 23), a first-trimester miscarriage (n = 19) or a normal term delivery (n = 117) were included in this study. Serum was collected from the initial pregnancy test, 11 days after a day 3 embryo transfer, and all samples were analysed for IL-2 sRalpha, TNF-alpha and IFN-gamma by commercially available enzyme-linked immunosorbent assay (ELISA) kits., Results: IL-2 sRalpha levels were significantly higher in patients with an early pregnancy loss compared with patients with a normal term delivery (849.5 +/- 69.6 versus 693.5 +/- 31.2 pg/ml, P = 0.02), and a cut-off point of IL-2 sRalpha >1000 pg/ml predicted a poor pregnancy outcome (44.4 versus 22.7% pregnancy loss, IL-2 sRalpha >or=1000 versus IL-2 sRalpha <1000 pg/ml; P = 0.02). IFN-gamma-positive patients had twice the risk for poor IVF pregnancy outcome compared with IFN-gamma-negative subjects (40.8 versus 20.0%, respectively; P < 0.02), including a significantly lower implantation rate (37.6 +/- 0.05 versus 50.0 +/- 0.03%, respectively; P = 0.02). There was no difference in pregnancy outcome based upon serum levels, or the ability to detect the presence of TNF-alpha. No differences in levels of these cytokines were found based on the aetiology of the patients' infertility., Conclusions: Elevated maternal serum levels of IL-2 sRalpha and IFN-gamma as early as 11 days after embryo transfer are associated with poor IVF pregnancy outcome.

Background: Germinal vesicle transplantation (GVT) provides a means of investigating interactions between karyoplasts and cytoplasts isolated from different cells. Technically, GVT can be accomplished with a high degree of efficiency without compromising the maturation of either the human or mouse oocyte nucleus. Although maturation, fertilization and preimplantation development have been established using GVT, full-term development has been reported only after supplementation with fresh mature ooplasm. In this study, we assess the ability of immature oocytes collected from gonadotrophin-primed ovaries to mature in vitro after GVT and develop to full-term., Methods: GV oocytes were retrieved from either non-stimulated or pregnant mare's serum gonadotrophin (PMSG)-primed female mice. Microsurgically isolated GV karyoplasts were transplanted into previously enucleated oocytes. Oocytes successfully reconstituted by electrofusion were cultured for 14 h to allow nuclear maturation. Metaphase II oocytes were subjected to Piezo-ICSI, and those fertilized normally were cultured to the blastocyst stage. Some such embryos were transferred to pseudopregnant female mice to examine their potential for normal development. Cumulus-denuded non-manipulated oocytes that were matured in vitro served as controls., Results: The reconstitution and maturation rates were comparable in oocytes isolated from PMSG-primed and from unstimulated ovaries. The rate of normal fertilization in oocytes from primed ovaries was significantly higher than that of their non-primed counterparts (63.5 versus 39.6%; P < 0.01). This difference was also confirmed in terms of blastocyst development (31.8 versus 7.9%; P < 0.01). Of a total of 70 embryos transferred to the oviduct of five recipient mice, 21.4% developed to normal live offspring. All developed as normal adults and proved to be fertile. The live birth rate was comparable to that obtained using non-manipulated control oocytes (22.3%)., Conclusions: Higher rates of fertilization and blastocyst formation were obtained after GVT of mouse oocytes isolated from PMSG-primed ovaries compared with their non-primed counterparts. These represent the first mouse offspring derived from in vitro matured, cumulus-denuded oocytes treated by allo-GVT and fertilized by ICSI. Thus, GVT appears not to impair oocyte maturation, fertilization and pre- and post-implantation development and, after gonadotrophin priming, allows generation of healthy mouse offspring without mature ooplasm supplementation.

Background: Aggressive immobilization of sperm prior to ICSI significantly improves fertilization rates, but the mechanism of this effect is not yet clear. This study was performed in order to assess the characteristics of mechanically immobilized human sperm by transmission electron microscope (TEM)., Methods: Sperm obtained from ejaculated semen samples from three different donors were immobilized in a standard manner for ICSI. They were then injected into the perivitelline space of mouse oocytes in order to be able to locate them by TEM. Intact motile sperm injected subzonally served as controls (n=160). Finally, the 'carrier' oocytes were fixed and processed for TEM., Results: A total of 300 sperm were mechanically immobilized and inserted into the perivitelline space of mouse oocytes. Ultrathin sections revealed consistent alterations in the acrosomal region including disruption of the plasma membrane, and disruption, vesiculation or even loss of the acrosome. Thus, all of the sperm assessed had undergone some disorganization of the head, in contrast to a majority of control sperm., Conclusions: Immobilization of sperm for ICSI by compressing and rolling the sperm tails induces a variable disruption and sometimes loss of the acrosome. This could well be a reason for the higher success rates when ICSI is performed using immobilized sperm.

Background: Y chromosome microdeletions are associated with severe male factor infertility. In this study, the success rate of testicular sperm retrieval was determined for men with deletions of AZF regions a, b or c., Methods: AZF deletions were detected by PCR of 30 sequence-tagged sites within Yq emphasizing the AZFa, b and c regions. Semen analysis and diagnostic testis biopsy or testicular sperm extraction (TESE) findings were correlated with the specific AZF region deleted., Results: A total of 78 men with AZF deletions included three with AZFa deletion, 11 with AZFb, 42 with AZFc, 16 with AZFb+c and six with Yq (AZFa+b+c). All men with AZFa, AZFb, AZFb+c and Yq deletions were azoospermic and no sperm were found with TESE or biopsy. Of men with isolated AZFc deletion, sperm were found in 75% (9/12) by TESE and 45% (9/20) on biopsy (56% overall); 62% (26/42) were azoospermic and 38% (16/42) severely oligozoospermic. A total of 7 patients with deletion patterns that included the complete AZFa region and 23 that included the complete AZFb region who underwent TESE or biopsy did not have sperm detected by these surgical measures., Conclusions: Microdeletion of the entire AZFa or AZFb regions of the Y chromosome portends an exceptionally poor prognosis for sperm retrieval, whereas the majority of men with AZFc deletion have sperm within the semen or testes available for use in IVF/ICSI.

Background: Breast cancer chemotherapy commonly causes premature ovarian failure and infertility. Because increased estrogen levels are thought to be potentially risky in breast cancer patients, natural cycle IVF (NCIVF) has been used to preserve fertility and treat infertility in these women., Methods: Twelve women with breast cancer received 40-60 mg tamoxifen for 6.9 +/- 0.6 days beginning on days 2-3 of their menstrual cycle (15 cycles), and had IVF (TamIVF) with either fresh embryo transfer (six cycles) or cryopreservation (nine cycles). They were compared to a retrospective control group (n = 5) who had natural cycle IVF (NCIVF, nine cycles)., Results: Cycle cancellation was significantly less frequent in TamIVF, compared with NCIVF (1/15 versus 4/9, P < 0.05). Compared with NCIVF, TamIVF patients had a greater number of mature oocytes (1.6 +/- 0.3 versus 0.7 +/- 0.2, P = 0.03) and embryos (1.6 +/- 0.3 versus 0.6 +/- 0.2, P = 0.02) per initiated cycle. TamIVF resulted in the generation of embryo(s) in every patient (12/12) while only three out of five patients had an embryo following NCIVF. Two out of six patients in TamIVF, and 2/5 in NCIVF conceived. One patient in the TamIVF group delivered a set of twins. After a mean follow up of 15 +/- 3.6 months (range 3-54), none of the patients had a recurrence of cancer., Conclusions: Tamoxifen stimulation appears to result in a higher number of embryos and may provide a safe method of IVF and fertility preservation in breast cancer patients.

Background: This study describes the technical approaches used in treatment of age-related oocyte aneuploidy, the efficiency of each step of nuclear transplantation into mouse and human oocytes, and the ability of germinal vesicle (GV) transplantation to restore artificially induced ooplasmic damage. Finally, it examines the possibility of constructing viable female gametes by transferring diploid somatic cell nuclei into enucleated oocytes., Methods: GV stage mouse oocytes were collected from unstimulated ovaries, and human GV oocytes were donated from consenting patients undergoing ICSI. Stromal (somatic) cells were isolated from uterine biopsies of consenting patients. Mouse cumulus cells were obtained after ovarian stimulation. GV ooplasts prepared by removing nuclei were transplanted either with GV nuclei or with somatic cells by micromanipulation. Grafted oocytes were electrofused and cultured to allow maturation, following which they were inseminated or analysed cytogenetically. Ooplasmic dysfunction was induced by photosensitization with a mitochondria-specific fluorescent dye., Results: GV transplantation had an overall efficiency of 87 and 73% in the mouse and humans respectively. Maturation rates of 95 (mouse) and 64% (human) following reconstitution were comparable with those in control oocytes, as was the incidence of aneuploidy for five chromosome-specific probes after aneuploidy among the reconstituted oocytes. Photosensitization of oocytes significantly reduced the maturation rate to 4.2%, whereas 61.9% of oocytes matured after transfer of photosensitized GV karyoplasts into healthy ooplasts, with 52% of these mature oocytes being successfully fertilized by ICSI. Enucleated immature oocytes receiving mouse cumulus or human endometrial cell nuclei extruded a polar body in >40% of cases. Five out of seven successfully transferred aged human nuclei exhibited the expected number of signals with five chromosome-specific probes suggesting an appropriate chromosome separation in young ooplasm., Conclusions: Nuclear transplantation itself does not appear to interfere with chromosome segregation and can possibly rescue oocytes with damaged mitochondria. Finally, immature mouse ooplasm supported separation of somatic chromosomes to expected numbers, implying that haploidization may be occurring. The roles of genetic imprinting and fidelity of chromosome segregation are unknown.

Background: Although ICSI provides a way of treating azoospermic men, concern has been raised about the potential risk for transmission of genetic abnormalities to the offspring. We quantified the incidence of chromosomal abnormalities in epididymal and testicular sperm retrieved from azoospermic patients undergoing ICSI., Methods: Individual testicular sperm were collected from testicular biopsies with an ICSI pipette, and epididymal sperm were retrieved by microsurgical epididymal sperm aspiration. Samples were processed by fluorescent in-situ hybridization (FISH) for chromosomes 18, 21, X and Y and the results compared with those from normal ejaculated samples., Results: The overall aneuploidy rate of 11.4% in men with non-obstructive azoospermia was significantly higher (P = 0.0001) than the 1.8% detected in epididymal sperm from men with obstructive azoospermia and also the 1.5% found in ejaculated sperm. No significant difference was found between the epididymal and ejaculated samples. When the chromosomal abnormalities were analysed, gonosomal disomy was the most recurrent abnormality in both obstructive and non-obstructive azoospermic patients, while autosomal disomy was the most frequent in ejaculated sperm., Conclusions: Sperm of non-obstructive azoospermic men had a higher incidence of chromosomal abnormalities, of which sex chromosome aneuploidy was the most predominant. Genetic counselling should be offered to all couples considering infertility treatment by ICSI with testicular sperm.

Background: Ethical constraints limit the ability to study peri-implantation phase human endometrium. In this study, the donor oocyte model was used to study candidate endometrial markers of uterine receptivity., Methods: Archived, paraffin-embedded tissue obtained by endometrial biopsy during cycle days 21-23 of patients undergoing 'mock' hormonal treatment cycles were evaluated by standard histological criteria and immunohistochemical staining for alpha v beta 3 integrin and glycodelin. All of these patients (n = 101) had undergone a donor oocyte embryo transfer cycle utilizing the exact same hormonal protocol., Results: Histological evaluation revealed 62 (61.3%) in-phase, 34 (33.7%) dyssynchronous, 2 (2.0%) immature and 3 (3.0%) advanced endometria. The clinical outcomes of patients with either in-phase or dyssynchronous endometria were similar. Very strong correlations were noted between endometrial glandular dating and either alpha v beta 3 integrin or glycodelin immunostaining intensity (P < 0.001 for both). Glycodelin and alpha v beta 3 integrin immunostaining intensities were also highly correlated with each other (P < 0.001)., Conclusions: Throughout the time period corresponding to the putative window of maximal endometrial receptivity (cycle days 21-23) a dynamic process was observed in exogenous hormonal replacement cycles characterized by a rapid histological advancement of endometrial glandular elements as well as progressive alpha v beta 3 integrin and glycodelin expression.

Transplanting a germinal vesicle (GV) from an aged woman's oocyte into a younger ooplasm has been proposed as a possible way to reduce the incidence of oocyte aneuploidy which is considered to be responsible for age-related infertility. In this study, we have assessed the efficiency of each step involved in nuclear transplantation-specifically cell survival, nuclear-cytoplasmic reconstitution, and the capacity of the reconstituted oocytes for in-vitro maturation. In addition, we have evaluated the fertilizability and karyotypic status of the manipulated oocytes by intracytoplasmic sperm injection (ICSI) and fluorescent in-situ hybridization technique respectively. Nuclear transplantation was accomplished with an overall efficiency of 73%. Due to the limited availability of materials, most nuclear transplantation procedures were performed between sibling oocytes. The maturation rate of 62% following reconstitution was comparable with that of control oocytes, as was the incidence of aneuploidy among the reconstituted oocytes. The ICSI results of the reconstituted oocytes yielded a survival rate of 77%, a fertilization rate of 52%, and a satisfactory early embryonic cleavage. Furthermore, in a limited number of observations where the nucleus of an aged oocyte was transferred into a younger ooplasm, there was an appropriate chromosomal segregation. These findings demonstrate that human oocytes reconstituted with GV nuclei are able to undergo maturation, fertilization, and early embryo cleavage, and maintain a normal ploidy. Although in-vitro maturation seems to be a limiting step, this technique would allow us to investigate further the nuclear-ooplasmic relationship during meiotic maturation.

Historically, follicular stimulation protocols have included both FSH and LH in an attempt to mimic the physiology of normal human folliculogenesis. However, many recent gonadotrophin administration regimens have completely eliminated LH bioactivity. The importance and the amount of LH necessary for optimal follicular stimulation has been a topic of debate. Several recent studies have added to our understanding of the actions of androgens, oestrogens, gonadotrophins, and insulin on the follicle-oocyte unit, allowing a less speculative approach. Moreover, the availability of human gonadotrophins synthesized by recombinant DNA technology and gonadotrophin-releasing hormone (GnRH) antagonists, should soon permit a precise in-vivo assessment and re-evaluation of the historical 2-cell, two-gonadotrophin hypothesis. These pharmacological tools may also provide essential insights into the physiological roles of FSH and LH in human follicular development and oocyte maturation. The recombinant gonadotrophins give clinicians the unique opportunity to tailor ovarian stimulation regimens according to the patient's medical history, in an effort both to maximize oocyte yield and to improve oocyte quality.

Although great progress has been made in both the investigation and treatment of infertility, a considerable number of patients still fail to conceive. Spermatogenic failure and/or oocyte ageing appear to be responsible for a large proportion of cases. The use of donor gametes may bring legal, ethical and even social problems of acceptance that can discourage infertile couples from the donor route. Fortunately, emerging reproductive technologies and preliminary results from animal experiments provide some hope for alternative sources of gametes through which these infertile patients can finally conceive their own genetic child. In conjunction with intracytoplasmic sperm injection (ICSI), fertilization of human oocytes with immature sperm precursors, e.g. spermatids and even secondary spermatocytes, has resulted in healthy babies. Pregnancies have also resulted from the use of spermatids derived from in-vitro spermatogenesis. In the mouse, even primary spermatocytes appear able to participate in normal embryogenesis. In view of the possibility for transplantation and even xenotransplantation of spermatogonia to a host testis in animals, a similar use of human male stem cells might provide an attractive source for the treatment of males with arrested spermatogenesis, as well as male cancer patients. Transplantation of somatic cell nuclei and their haploidization within oocytes may prove to be a practical way of eradicating age-related aneuploidy and so constitute an innovative source of healthy oocytes. Most importantly, however, the safety of the procedures described here needs to be proven before their application to the human arena. Finally, we discuss the implications of cytoplasmic quality and of genetic imprinting in the context of these manipulations.

To assess the association of zona pellucida micromanipulation and subsequent development of monozygotic twins, cases of assisted embryo hatching (AH) and intracytoplasmic sperm injection (ICSI) were identified and related to treatment type, implantation and zygosity data. Embryology records from all patients undergoing in-vitro fertilization (IVF) at this centre from January 1995 to March 1998 were reviewed. In this study, 3546 transfer cycles were completed, with clinical pregnancy established in 1911 (54% per transfer) patients undergoing a single IVF cycle. These pregnancies occurred in 1674 (88%) IVF cycles, 120 (6%) donor oocyte cycles (DER), and 117 (6%) frozen embryo transfer (FET) cycles. During the study period, 23 cases of monozygotic (MZ) twins were identified, representing an overall frequency of 1.2%. Chorionicity was determined by transvaginal ultrasound at 7 weeks when the number of embryos transferred was less than the number of fetal heart-beats, or when >1 fetal heartbeat per gestational sac was seen. Zygosity was confirmed by placental evaluation at delivery, and corroborated the antenatal diagnosis in all cases. Among IVF study patients the frequency of MZ twinning was not statistically different between zona manipulated and zona intact subgroups. While this investigation is the largest to date describing the relationship between MZ twins and zona procedures, studies with even greater statistical power are needed to clarify it more precisely, particularly in DER and FET settings. A greater overall frequency of MZ twinning for IVF patients may be a function of the higher number of embryos transferred in IVF, rather than discrete zona manipulations.

The first large survey on the public perception of infertility and its treatment was conducted in six European countries, the USA and Australia. A representative sample of 8194 adults was polled, using standard validated methodology. The results obtained highlighted the following major aspects: (i) infertility is perceived as a disease by less than half of the people surveyed (38%), in contrast to the accepted medical opinion; (ii) awareness about the definition and incidence of infertility is relatively low, despite the fact that half of the people polled claimed to know someone affected by infertility; (iii) close to 90% of the adults surveyed knew about in-vitro fertilization (IVF), but less than one-quarter of them knew about the chances of success of this assisted reproductive technology; and (iv) when confronted with the knowledge that the cost of three IVF cycles is roughly equivalent to the cost of a hip replacement (a commonly reimbursed procedure), a large majority (70%) of the individuals interviewed agreed that IVF should be reimbursable.

The commercial availability of highly purified, s.c. administered urinary follicle stimulating hormone (FSH) preparations for ovarian stimulation marked the beginning of a new era in the treatment of infertility. As these new formulations contain essentially no luteinizing hormone (LH), supplemental LH may be needed for optimal folliculogenesis. It was the aim of this pilot study to compare fertilization rates, embryo morphology, implantation rates and pregnancy outcomes prospectively in two age-matched patient groups: women who received highly purified FSH (FSH-HP) (n = 17), and women who received FSH-HP plus recombinant human LH (rhLH, n = 14) throughout ovarian stimulation. All patients received mid-luteal pituitary down-regulation with s.c. gonadotrophin-releasing hormone agonist (GnRHa) (leuprolide). Mean implantation rates were 26.9 and 11.9% in the FSH-HP only and FSH-HP + rhLH groups respectively. The mean clinical pregnancy/initiated cycle rate was 64.7 and 35.7% for the FSH-HP only and FSH-HP + rhLH patients respectively. FSH-HP patients and FSH-HP + rhLH patients achieved clinical pregnancy/transfer rates of 68.8 and 45.5% respectively. One patient in the FSH-HP + rhLH group had a spontaneous abortion; no pregnancy losses occurred in the FSH-HP only group. There were more cancellations for poor ovarian response among FSH-HP + rhLH patients (n = 3) than among FSH-HP patients (n = 1). The trend toward better pregnancy outcomes among patients who received FSH-HP without supplemental rhLH did not reach statistical significance. It is postulated that appropriate endogenous LH concentrations exist despite luteal GnRHa pituitary suppression, thereby obviating the need for supplemental LH administration.

Transplanting a germinal vesicle (GV) to another enucleated oocyte provides a possible way to avoid age-related aneuploidy in metaphase II (MII) oocytes from older women. This study was conducted to examine the efficiency of each step of nuclear transplantation as reflected in the survival and maturation capacity of immature mouse oocytes subjected to this procedure. GV stage oocytes were retrieved from unstimulated ovaries. A GV removed with a small amount of cytoplasm (karyoplast) was transferred subzonally into a previously enucleated oocyte, which was then exposed to direct current to promote fusion. Such reconstituted oocytes were placed in culture to allow maturation, and some that had extruded a first polar body were fixed and processed for chromosome analysis. Each step of nuclear transplantation - survival, enucleation, grafting, and reconstitution - was successful in >90%, with the overall efficiency of reconstitution being 80%. The observation of normal karyotypes confirmed that the procedure did not increase chromosomal aneuploidy. An electrolytic medium, revealed to be superior for the reconstitution procedure, also allowed haploidization of the transplanted nucleus. These findings suggest that this technique can be applied to study the effects of a 'younger' woman's ooplasm on the disjunction of an 'older' woman's chromosomes during meiosis I.

The evident ability of the intracytoplasmic sperm injection (ICSI) procedure to achieve high fertilization and pregnancy rates regardless of semen characteristics has induced its application with spermatozoa surgically retrieved from azoospermic men. Here, ICSI outcome was analysed in 308 cases according to the cause of azoospermia; four additional cycles were with cases of necrozoospermia. All couples were genetically counselled and appropriately screened. Spermatozoa were retrieved by microsurgical epididymal aspiration or from testicular biopsies. Epididymal obstructions were considered congenital (n = 138) or acquired (n = 103), based on the aetiology. Testicular sperm cases were assessed according to the presence (n = 14) or absence (n = 53) of reproductive tract obstruction. The fertilization rate using fresh or cryopreserved epididymal spermatozoa was 72.4% of 911 eggs for acquired obstructions, and 73.1% of 1524 eggs for congenital cases; with clinical pregnancy rates of 48.5% (50/103) and 61.6% (85/138) respectively. Spermatozoa from testicular biopsies fertilized 57.0% of 533 eggs in non-obstructive cases compared to 80.5% of 118 eggs (P = 0.0001) in obstructive azoospermia. The clinical pregnancy rate was 49.1% (26/53) for non-obstructive cases and 57.1% (8/14) for testicular spermatozoa obtained in obstructive azoospermia, including three established with frozen-thawed testicular spermatozoa. In cases of obstructive azoospermia, fertilization and pregnancy rates with epididymal spermatozoa were higher than those achieved using spermatozoa obtained from the testes of men with non-obstructive azoospermia.

The relationship between a previously undetected Chlamydia trachomatis infection, tubal infertility, immunity to heat shock proteins and subsequent in-vitro fertilization (IVF) outcome was evaluated. Women with tubal occlusion, with or without hydrosalpinges, and no history of C. trachomatis infection were tested for circulating antibodies to the human 60-kDa heat shock protein (Hhsp60), the C. trachomatis 10-kDa heat shock protein (Chsp10) and C. trachomatis surface antigens prior to their initial IVF cycle. Sera were obtained from 50 women whose male partners were infertile, 58 women with tubal occlusion but no hydrosalpinx and 39 women with tubal occlusions plus hydrosalpinx. Clinical pregnancies were documented in 68% of the women with male factor infertility. This was higher than the 43.1% rate in women with tubal occlusions (P = 0.04) and the 41% rate in women with hydrosalpinx (P = 0.02). C. trachomatis antibodies were present in one (2%) women with male factor infertility as opposed to 15 (25.9%) women with tubal occlusion (P = 0.003) and 13 (33%) with hydrosalpinx (P < 0.0001). Antibodies to Chsp10 were more prevalent in women with hydrosalpinx (46.8%) than in women with male factor infertility (P < 0.0001, 6%) or tubal occlusion (P = 0.0009, 15.5%). Hhsp60 antibodies were equally more prevalent in women with tubal occlusion plus (46.8%) or minus hydrosalpinx (41.4%) than in women with male factor infertility (P < 0.0002). Hhsp60 was more prevalent in those women positive for Chsp10 (P = 0.02) or C. trachomatis (P = 0.04) antibodies than in women lacking these antibodies. There was no relationship between any of the antibodies measured in sera and IVF outcome.

The impact of intracytoplasmic sperm injection (ICSI) on cryopreserved zygotes and embryos was evaluated by comparing embryo survival and implantation between embryos derived from ICSI and those derived from standard insemination procedures. The study included patients whose excess zygotes and embryos were cryopreserved between September 1993 and December 1994 and who subsequently underwent a frozen embryo transfer. Embryo survival, clinical pregnancy rates per transfer and pregnancy outcome were compared. Three hundred and thirty eight cryopreservation cycles, during which 1471 embryos were cryopreserved, were included in this study. Of those, 961 were derived from oocytes fertilized by insemination in vitro and 510 were derived from oocytes fertilized by ICSI. A total of 690 of the embryos (451 in the insemination group and 239 in the ICSI group) have since undergone a thaw cycle. The embryo survival rates were similar between the two groups (70.5 and 73.2%, insemination and ICSI respectively) and were not significantly affected by the stage at cryopreservation. There was no significant difference in pregnancy rates per transfer (31.8 and 32.3%), the preclinical pregnancy loss rate (16.7 and 23.8%), or the clinical miscarriage rate (16.7 and 23.8%) between the insemination and the ICSI groups respectively. It is concluded that ICSI does not have an adverse impact on the survival and successful implantation of cryopreserved and thawed embryos.

With the introduction of intracytoplasmic sperm injection (ICSI), couples with severe male factor infertility have achieved fertilization and clinical pregnancy rates comparable to other in-vitro fertilization (IVF) patients. However, failure of fertilization still occurs in some patients despite the utilization of microsurgical sperm injection techniques. How such fertilization failure after ICSI might impact later ICSI treatment(s) is unknown. In this investigation, couples with complete fertilization failure after ICSI treated from August 1993 to August 1996 were identified (index cycle, n = 21). Additionally, fertilization data from any previous or subsequent infertility treatments were evaluated. Seven patients (33%) had at least one IVF treatment before the index cycle, although no deliveries occurred. Of patients with complete fertilization failure in the index cycle, 48% (n = 10) underwent at least one subsequent ICSI cycle which proceeded to oocyte retrieval. The remainder (n = 11) elected to discontinue treatment. Although six subsequent cycles were cancelled due to poor follicular response (< or = 2 mature oocytes), all patients electing to continue treatment eventually achieved a subsequent embryo transfer. The clinical pregnancy rate per transfer was 45.4% for this group; the delivery and ongoing pregnancy rate per transfer was 36.3%. Review of semen parameters, superovulation characteristics or other clinical parameters during the three study cycles (pre-index, index, and post-index) was not prognostic of fertilization success or reproductive outcomes in later treatments. Fertilization failure with ICSI therefore could not be predicted by prior cycle performance, although total immotility of spermatozoa at time of oocyte retrieval, total teratozoospermia, and low oocyte yield were common characteristics of couples experiencing complete fertilization failure with ICSI. These findings suggest that fertilization failure in one ICSI cycle does not preclude successful fertilization and delivery in a later ICSI treatment.

Electroejaculation has been successfully used for sperm procurement in anejaculatory men desiring fertility. However, electroejaculates typically have normal sperm numbers but poor motility, morphology, and functional deficiencies. Here we report the pregnancy outcome of a series of couples undergoing combined electroejaculation and in-vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI). In all, 13 couples underwent a total of 18 cycles. The aetiologies of anejaculation included history of retroperitoneal lymph node dissection for testicular cancers, spinal cord injury and psychogenic causes. ICSI was performed on 192 oocytes, resulting in a fertilization rate of 75.5%. A total of 15 embryo transfers were performed using a total of 51 embryos. Clinical pregnancy rate, as defined by positive fetal heart rate(s) using vaginal sonography, was 55.6% per retrieval; implantation rate was 33.3% per embryo. These rates appear to be similar to those obtained in standard IVF for non-male factor infertility, or ICSI for male factor infertility. The use of ICSI for electroejaculates undoubtedly provides these couples with the highest chance of pregnancy.

Two-cell mouse embryos (B6D2F1) were cultured in the presence or absence of 100 microg/ml monoclonal antibodies specific for the mammalian 60 kDa (HSP60), 70 kDa (HSP70) and 90 kDa (HSP90) heat shock proteins. Embryo development was evaluated after 3, 5 and 7 days in culture by determining the number of blastocysts, hatched blastocysts and outgrown trophoblasts at the successive time points. At day 3, only 29% (22/75) of the embryos cultured with anti-HSP60 antibody developed to the blastocyst stage (P < 0.0001) as compared to 67% (31/46) of the embryos cultured with anti-HSP70, 72% (43/60) cultured with anti-HSP90, and 79% (49/62) in medium plus mouse IgG1. By day 5, hatched embryos were present in 28% (13/ 46) of the cultures containing anti-HSP70 (P < 0.0001), as opposed to 57% (34/60) containing anti-HSP90 and 73% (45/62) containing IgG1. At day 7, outgrown trophoblasts were observed in 9% (4/46) of cultures containing anti-HSP70 (P < 0.0001), 45% (27/60) containing anti-HSP90 (P < 0.01) and 66% (41/62) cultured in medium plus IgG1. Antibodies to different heat shock proteins exerted a detrimental effect on mouse embryo development at unique development stages. Immune sensitization to heat shock proteins may be a cause of reproductive failure.

The purpose of this study was to investigate any influence of maternal and/or paternal age on gamete characteristics and pregnancy outcomes in intracytoplasmic sperm injection (ICSI) cycles. In all, 821 consecutive ICSI cases were analysed retrospectively. While a significant linear decline in semen volume was detected, no significant differences in the concentration, motility or morphology of the spermatozoa were found with paternal ageing. A significant decline in the number of oocytes retrieved and the number of mature oocytes obtained was found with advancing maternal age. An increase in the occurrence of digyny was noted with parental ageing, while no difference in single or bipronuclear fertilization was found. Older women had a decreased incidence of single pronucleus formation and an increase in digyny, but no significant difference in the percentage of oocytes that underwent two-pronuclear fertilization was detected with regard to maternal ageing. Pregnancy outcomes were not influenced by the age of the male partner, while a strong negative correlation was found with maternal ageing. To better analyse male partner ageing as a factor affecting pregnancy outcome, we analysed a subgroup of patients with a female partner aged <35 years who underwent ICSI. No paternal influence on ICSI pregnancy outcome was found in this subgroup of patients. We conclude that the influence on pregnancy outcome after ICSI is related mostly to maternal and not paternal age.

Certain patients have a tendency for high response to gonadotrophin therapy which is often not ameliorated with prior gonadotrophin-releasing hormone agonist (GnRHa) suppression. As a result, these patients are frequently cancelled and often experience ovarian hyperstimulation syndrome (OHSS) episodes during in-vitro fertilization (IVF)-embryo transfer cycles. Patients with polycystic ovarian syndrome (PCOS) have been noted to be particularly sensitive to exogenous gonadotrophin therapy. We have developed a protocol which is effective in improving IVF outcome in high responder patients, including those with PCOS. Oral contraceptive pills (OCP) are taken for 25 days followed by s.c. leuprolide acetate, 1 mg/day, which is overlapped with the final 5 days of oral contraceptive administration. Low-dose gonadotrophin stimulation is then initiated on the third day of withdrawal bleeding in the form of either human menopausal gonadotrophins or purified urinary follicle-stimulating hormone at a dosage of 150 IU/day. Over a 5 year period, we reviewed our experience utilizing this dual method of suppression in 99 cycles obtained in 73 high responder patients. There were only 13 cancellations prior to embryo transfer (13.1%). The clinical and ongoing pregnancy rates per initiated cycle were 46.5 and 40.4% respectively. Only eight patients experienced mild-moderate OHSS following treatment. For those patients who had undergone previous IVF-embryo transfer cycles at our centre, significant improvements were noted in oocyte fertilization rates, embryo implantation rates and clinical/ongoing pregnancy rates with this protocol. Hormonal analyses revealed that the chief mechanism may be through an improved luteinizing hormone/follicle-stimulating hormone ratio following dual suppression. An additional feature of this dual method of suppression is significantly lower serum androgen concentrations, particularly dehydroepiandrosterone sulphate.

The objective of this study was to compare prospectively pregnancy outcome as it is related to ultrasonic endometrial echo pattern in women exposed to diethylstilboestrol (DES) in utero by their mother's consumption with women not exposed to DES, all of whom were undergoing in-vitro fertilization (IVF). Pregnancy outcome relative to endometrial thickness and pattern was evaluated in 540 cycles of IVF including DES (n = 50) and non-DES-exposed (n = 490) women. Endometrial patterns were designated as p1 = solid; p2 = ring; and p3 = intermediate. DES patients exhibited p1 more often than the majority of the non-DES-exposed group. There was no significant difference in endometrial thickness among the cycles where p1 was noted when comparing the DES (10.3 mm) with the non-DES-exposed (10.7 mm) groups. Notably, within the group exhibiting p1, no pregnancies occurred in the 18 cycles of DES-exposed women compared with a 39.2% clinical pregnancy and 36.5% delivery rate in the non-DES-exposed controls (P < 0.0001 and P = 0.008 respectively). Pregnancy rates were not significantly different in the cycles where the other endometrial patterns were found when comparing the two groups. The impact of uterine shape on pregnancy outcome was also investigated. A T-shaped uterine configuration was noted in 11 out of 18 (61.1%) cycles of DES-exposed women with pattern p1 compared with nine out of 23 (39.1%) with pattern p2. Of cycles where a T-shaped uterus was demonstrated, none out of 11 (0%) with pattern p1 compared with four out of nine (44.4%) with pattern p2 resulted in pregnancy (P = 0.026). These data suggest that endometrial pattern is one of the most significant variables for pregnancy outcome in DES-exposed women undergoing IVF.

The detection of congenital uterine anomalies has increased because of heightened physician awareness and improved diagnostic modalities. The occurrence of a twin pregnancy occupying separate horns of a bicornuate uterus has been reported only sporadically in the literature. This is the first reported case resulting after in-vitro fertilization and embryo transfer.

This study was conducted to determine whether the mode of sperm immobilization prior to intracytoplasmic sperm injection (ICSI) influences fertilization by immature spermatozoa. Of the 837 ICSI cycles evaluated, 81 were performed with epididymal or testicular spermatozoa; 35 cycles with epididymal spermatozoa immobilized in the standard fashion resulted in fertilization and pregnancy rates of 48.3 and 51.4% respectively. When a more aggressive sperm immobilization technique (i.e. permanently crimping the sperm flagellum between the midpiece and the rest of the tail) was applied in 17 cycles, the resultant fertilization and pregnancy rates were significantly (P < 0.05) higher: 82.0 and 82.4% respectively. Similar increases in fertilization and ensuing pregnancy rates were also observed in ICSI cycles with the aggressive immobilization of frozen-thawed epididymal spermatozoa (eight cycles) versus standard immobilization (16 cycles). However, the fertilization rates for ICSI using testicular spermatozoa (five cycles) were basically the same, regardless of the immobilization technique. Furthermore, for ejaculated spermatozoa (756 cycles), the fertilization rates following aggressive sperm immobilization were also positively affected (73.4%), although no statistical differences in the clinical pregnancy rates were found. Because aggressive immobilization appears to affect sperm membrane permeabilization, the enhanced fertilization patterns observed in immature spermatozoa following aggressive immobilization may suggest a different membrane constitution in these spermatozoa. These findings indicate that immature gametes may require additional manipulation to enhance the post-ICSI events essential for adequate nuclear decondensation.

The aim of this study was to analyse the various reactions displayed by the oolemma to the penetrating pipette during intracytoplasmic sperm injection (ICSI) and correlate them with clinical factors, oocyte survival and fertilization patterns. Three types of oolemma responses were observed: normal breakage, when the injection needle created an invagination that ruptured at the approximate centre of the egg; sudden breakage, when the membrane broke without creating a funnel; and difficult breakage, when the membrane did not break or broke after several penetration attempts. A total of 2928 oocytes were analysed with the following observations: 73.9% (n = 2164) experienced normal breakage, 11.8% (n = 345) sudden breakage, and 14. 3% (n = 419) difficult breakage. The survival rate and number of normally fertilized oocytes were significantly lower and the incidence of digynic oocytes was significantly higher in the sudden breakage group; furthermore, in this group a significantly shorter length of stimulation was observed along with lower serum oestradiol concentrations when compared to oocytes experiencing normal and difficult breakage patterns. These recorded patterns were predictive of the survival and fertilization ability of the injected oocytes, as well as the incidence of digyny. The link between membrane behaviour and various clinical parameters appears to indicate a correlation between the modality of stimulation and oolemma characteristics.

There is a significant decline in human fecundity with advancing age. A significant decrement in success rates is also seen in older women undergoing assisted reproduction, including in-vitro fertilization. We have observed a drop in the ongoing pregnancy rate per embryo transfer, from 48.8% in women aged < 30 years to 13.6% in women aged > or = 42 years. Embryo implantation rates also decline in a linear fashion, from 29% in women < 34 years to approximately 5% at age 42. We observed that the impaired implantation efficiency seen in older women is apparently independent of the magnitude of their stimulation response. Oocyte factors are felt to be primarily responsible; however, some available data suggest that uterine factors, e.g. diminished endometrial receptivity, may also play a role. There are presently no treatment strategies apart from oocyte donation, which have been shown to significantly improve implantation efficiency in older women. However, recent efforts have focused on the continued development of improved stimulation protocols, facilitation of embryo implantation by zona pellucida micromanipulation, and the possibility of screening preimplantation embryos for aneuploidy.

The purpose of this study was to assess the genetic status of abnormal zygotes following assisted fertilization. Dispermic, monopronucleated and digynic zygotes were allowed to cleave intact or after enucleation, and on the biopsied blastomeres, multiplex polymerase chain reaction and fluorescent in-situ hybridization were performed. It was found that the distal pronucleus was usually male in origin in dispermic embryos, and that the sex ratio was restored when they were enucleated; however, they became mosaic at metaphase and their genetic heterogeneity was not restored after enucleation. Monopronucleated zygotes derived from standard in-vitro insemination can be transferred to the patient, since they usually showed normal diploid complement in their cells. On the contrary, single-pronucleated zygotes derived from intracytoplasmic sperm injection were usually activated parthenogenetically, but not fertilized. Digynic embryos, unlike dispermic ones, had a very low incidence of mosaicism, and when present, such mosaicism originated at a later embryo division. Most of the digynic embryos were triploid, indicating that the first division was normal and bipolar; moreover, when the female pronucleus was removed, they became diploid and their genetic status was considered normal. The recognition and understanding of fertilization abnormalities allow the identification of methods leading to their avoidance or correction.

To evaluate the role of endometrial thickness and pattern in in-vitro fertilization (IVF), these parameters were prospectively measured in 516 cycles of IVF with embryo transfer at our clinic. Pregnancy and embryo implantation rates were assessed for each mm of endometrial thickness and for each of three endometrial patterns. Embryo implantation, clinical and ongoing pregnancy rates were significantly higher in the patients with an endometrial thickness > 9 mm (24.4, 48.6 and 42.2% respectively) compared with those of < 9 mm (14.3, 16.0 and 11.7% respectively; P < 0.005). Endometrial thickness was negatively influenced by age and positively influenced by oestradiol concentration. The majority of patients (69.8%) exhibited a 'ring' endometrial pattern. Embryo implantation and clinical pregnancy (statistically significant), as well as ongoing pregnancy rates (not statistically significant), were lower in patients exhibiting the 'solid' pattern. Endometrial thickness is independent of pattern in its effect on pregnancy outcome. In conclusion, endometrial thickness > 9 mm as well as ring and intermediate endometrial patterns denoted a more favourable prognosis for pregnancy in IVF but thinner endometrium and those exhibiting a solid configuration had an acceptable pregnancy outcome.

Six cases of identical twin pregnancies which occurred in 2163 cycles of in-vitro fertilization during a 3 year period are reported. Monozygosity was confirmed when the number of fetuses exceeded the number of embryos replaced (n = 4) or when two concepti were observed in a single amniotic sac (n = 2). Each of the reported pregnancies resulted from replacement of embryos either with naturally thin zonae pellucidae or embryos whose zonae had been breached during micromanipulation for assisted fertilization (subzonal sperm insertion) or assisted hatching. That such cases exclusively gave rise to monozygosity suggests a link between the physical state of the zona pellucida, hatching, and generation of identical twins.

Preimplantation genetic diagnosis was performed in 122 embryos obtained by IVF from 11 patients carriers of haemophilia, Duchenne's muscular dystrophy, Barth's syndrome, cystic fibrosis, Pelizaeus-Merzbacher syndrome or Rett's syndrome. After multiplex polymerase chain reaction (PCR) or fluorescence in situ hybridization (FISH) analysis with multiple probes, 28 embryos diagnosed as not affected were replaced. Of these, eight implanted (28%) and produced three ongoing pregnancies, three deliveries of four babies and a biochemical pregnancy. However, one case screened for cystic fibrosis was misdiagnosed and the pregnancy was terminated. In order to evaluate the efficiency of multiplex PCR, 55 non-replaced embryos were reassessed by PCR or by FISH. Identical results were obtained in all cases. However, one embryo which had only X-chromosome specific amplification by PCR was found to be XO in all its cells by FISH. Although multiplex PCR is demonstrated to be reliable for sexing of human embryos, FISH has the additional advantages of supplying ploidy assessment while not being affected by contamination.

A short fluorescence in-situ hybridization (FISH) procedure using fluorochrome and digoxigenin labelled DNA probes was developed for application in human preimplantation embryos in order to analyse the five chromosomes most involved in human aneuploidy (X, Y, 18, 13 and 21). The chromosomes were fluorescent-stained and detected simultaneously in 157 blastomeres from 30 human embryos. Successful FISH analysis was achieved in 93% of the blastomeres. Aberrations for these chromosomes were found in 70% of abnormally developing monospermic embryos. The majority of normally developing monospermic embryos obtained from older patients were also chromosomally abnormal. By analysing all or most of the cells from these embryos, true mosaicism was distinguished from technique failure. Mosaic embryos, polyploid embryos with ploidies as high as 8n, haploid embryos, embryos monosomic for 13/21 and for X, and embryos trisomic for 13/21 and 18, were common in abnormally developing embryos. In contrast, aneuploidy was the main chromosome abnormality found in normally developing monospermic embryos.

A new technology called primer extension preamplification (PEP), which has been applied to single spermatozoa, increases the amount of polymerase chain reaction (PCR) templates by amplifying DNA of the whole genome. The current investigation was aimed at applying PEP to single human blastomeres. Two blastomeres with nuclei from arrested embryos were selected for this study. Using three different PEP protocols (experiments I, II and III), DNA from single blastomeres was amplified using 15-base oligonucleotide random primers. The efficiency of the procedure was determined by further amplifications of aliquots of the PEP products with two specific sequences. Three aliquots from each PEP product were used as PCR templates for the human X chromosome (X) or the exon 10 of the cystic fibrosis gene (CF). PCR amplified products were analysed by gel electrophoresis. In experiment I, when X primers were used, positive signals were detected in all 10 embryos (100%), 90.0% (18/20) of the blastomeres, and in 80.0% (96/120) of the replicates. When CF primers were amplified, all embryos (100%, 10/10), 90.9% (18/20) of the blastomeres and 78.3% (47/60) of the replicates were positive. In experiment II, efficiency was significantly reduced when total time for the procedure was minimized from 8 h to 5 h and 45 min. Although the time was further reduced to 4 h and 40 min in experiment III, the efficiency remained the same as in experiment I when the volume of PEP was reduced from 60 microliters (experiments I and II) to 40 microliters. One out of 132 control replicates (0.8%) was contaminated.(ABSTRACT TRUNCATED AT 250 WORDS)

Assisted hatching by zona drilling using acidic Tyrode's solution was performed during three randomized trials in 330 in-vitro fertilization patients. The trials were designed in order to study the overall effect of the procedure and whether characteristic patient [i.e. maternal age and basal levels of follicle stimulating hormone (FSH)] and embryonic features (i.e. zona pellucida thickness) are important for the decision to perform assisted hatching routinely. Couples (n = 137; Trial 1) in whom the female partner had normal basal FSH levels were randomized in a control group (without micromanipulation) and a zona drilling group (all embryos micromanipulated). The incidence of implantation (67/239; 28%) of zona-drilled embryos compared favourably with that of control embryos (49/229; 21%), but the difference was not significant. Retrospective analysis revealed that those embryos whose zonae were thicker than 15 microns were rescued. In order to test the validity of this finding, selective assisted hatching was performed on embryos with a poor prognosis in 163 other patients (Trial 2). The couples were randomized into a control group and a group in which embryos were selectively zona-drilled, based on zona thickness and other embryonic features. The rate of embryonic implantation in the selectively zona-drilled group was 25% (70/278), significantly (P less than 0.05) higher than that of control embryos (51/285; 18%). Although it was demonstrated retrospectively and prospectively that assisted hatching by zona drilling is effective in embryos with thick zonae (greater than or equal to 15 microns), patients whose embryos have thin (less than 13 microns) zonae may be jeopardized by the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Our objective was to evaluate and compare the efficacy and mechanisms of co-culturing mouse embryos with Vero cells in both Dulbecco's modified Eagle's medium/Ham's F12 (DMEM/F12) and human tubal fluid (HTF) culture medium. Two-cell CB6F1 mouse embryos were cultured either in the presence of Vero cells (group A) or in culture medium alone (group B). In DMEM/F12 significantly more morulae developed in group A than in group B on day 3 (91 versus 23%; P less than 0.01). In contrast, the mouse embryos grew rapidly in HTF and significant differences were noted only in later embryonic stages (on day 5; 86% and 50%, P less than 0.01 of group A and B respectively, hatching or hatched). Similar experiments using DF1 and ICR mouse strains also revealed enhanced embryo development in the presence of Vero cells. To determine whether the embryo-enhancing effects of Vero cells were due to the removal of toxins or to the secretion of embryotrophic factors, ICR mouse embryos were cultured in fresh media with cells (group A), without cells (group B) and in cell-free conditions using cell-conditioned media which were obtained in the presence (group C) or absence (group D) of embryos. These results demonstrated that completion of hatching was highest (52%; P less than 0.01) in group A after 6 days in culture. There were no significant differences between groups B, C and D (rates of total hatching 18, 17 and 17%, respectively). It is concluded that Vero cells improve the development of mouse embryos and this is likely to be due to removal of substances inhibitory to development.(ABSTRACT TRUNCATED AT 250 WORDS)

A retrospective analysis was performed on 64 cycles stimulated with human menopausal gonadotrophin and/or pure follicle-stimulating hormone (FSH) and oestrogen (E2) levels. The increase in serum E2 on the day of HCG administration did not correlate (r = 0.05) with the number of preovulatory oocytes (preovs) or with an increase or decrease in serum FSH (r = 0.31). However, the change in serum FSH showed a significant correlation with the number of preovs (r = -0.95, P = 0.013). The probability of obtaining two or more preovs was relatively greater (1.47x) than that of other IVF patients, when there was a drop in FSH of 5% on the day of human chorionic gonadotrophin administration.