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Study Question: Which couples with unexplained subfertility can expect increased chances of ongoing pregnancy with IVF compared to expectant management?Summary Answer: For couples in which the woman is under 40 years of age, IVF is associated with higher chances of conception than expectant management.What Is Known Already: The clinical indications for IVF have expanded over time from bilateral tubal blockage to include unexplained subfertility in which there is no identifiable barrier to conception. Yet, there is little evidence from randomized controlled trials that IVF is effective in these couples.Study Design, Size, Duration: We compared outcomes in British couples with unexplained subfertility undergoing IVF (n = 40 921) from registry data to couples with the same type of subfertility on expectant management. Those couples on expectant management (defined as no intervention aside from the advice to have intercourse) comprised a prospective nation-wide Dutch cohort (n = 4875) and a retrospective regional cohort from Aberdeen, Scotland (n = 975). We excluded couples who had tried for <1 year to conceive and also those with anovulation, uni- or bilateral tubal occlusion, mild or severe endometriosis or male subfertility i.e. impaired semen quality according to World Health Organization criteria.Participants/materials, Setting, Methods: We matched couples who received IVF and couples on expectant management based on their characteristics to control for confounding. We fitted a Cox proportional hazards model including patient characteristics, IVF treatment and their interactions to estimate the individualized chance of conception over 1 year-either following IVF or expectant management for all combinations of patient characteristics. The endpoint was conception leading to ongoing pregnancy, defined as a foetus reaching a gestational age of at least 12 weeks.Main Results and the Role Of Chance: The adjusted 1-year chance of conception was 47.9% (95% CI: 45.0-50.9) after IVF and 26.1% (95% CI: 24.2-28.0) after expectant management. The absolute difference in the average adjusted 1-year chances of conception was 21.8% (95%CI: 18.3-25.3) in favour of IVF. The effectiveness of IVF was influenced by female age, duration of subfertility and previous pregnancy. IVF was effective in women under 40 years, but the 1-year chance of an IVF conception declined sharply in women over 34 years. In contrast, in woman over 40 years of age, IVF was less effective, with an absolute difference in chance compared to expectant management of 10% or lower. Regardless of female age, IVF was also less effective in couples with a short period of secondary subfertility (1 year) who had chances of natural conception of 30% or above.Limitations, Reasons For Caution: The 1-year chances of conception were based on three cohorts with different sampling mechanisms. Despite adjustment for the three most important prognostic patient characteristics, namely female age, duration of subfertility and primary or secondary subfertility, our estimates might not be free from residual confounding.Wider Implications Of the Findings: IVF should be used selectively based on judgements on gain compared to continuing expectant management for a given couple. Our results can be used by clinicians to counsel couples with unexplained subfertility, to inform their expectations and facilitate evidence-based, shared decision making.Study Funding/competing Interest(s): This work was supported by Tenovus Scotland [grant G17.04]. Travel for RvE was supported by the Amsterdam Reproduction & Development Research Group [grant V.000296]. SB reports acting as editor-in-chief of HROpen. Other authors have no conflicts. [ABSTRACT FROM AUTHOR]

Study Question: How well does a previously developed dynamic prediction model perform in an external, geographical validation in terms of predicting the chances of natural conception at various points in time?Summary Answer: The dynamic prediction model performs well in an external validation on a Scottish cohort.What Is Known Already: Prediction models provide information that can aid evidence-based management of unexplained subfertile couples. We developed a dynamic prediction model for natural conception (van Eekelen model) that is able to update predictions of natural conception when couples return to their clinician after a period of unsuccessful expectant management. It is not known how well this model performs in an external population.Study Design, Size, Duration: A record-linked registry study including the long-term follow-up of all couples who were considered unexplained subfertile following a fertility workup at a Scottish fertility clinic between 1998 and 2011. Couples with anovulation, uni/bilateral tubal occlusion, mild/severe endometriosis or impaired semen quality according to World Health Organization criteria were excluded.Participants/materials, Setting, Methods: The endpoint was time to natural conception, leading to an ongoing pregnancy (defined as reaching a gestational age of at least 12 weeks). Follow-up was censored at the start of treatment, at the change of partner or at the end of study (31 March 2012). The performance of the van Eekelen model was evaluated in terms of calibration and discrimination at various points in time. Additionally, we assessed the clinical utility of the model in terms of the range of the calculated predictions.Main Results and the Role Of Chance: Of a total of 1203 couples with a median follow-up of 1 year and 3 months after the fertility workup, 398 (33%) couples conceived naturally leading to an ongoing pregnancy. Using the dynamic prediction model, the mean probability of natural conception over the course of the first year after the fertility workup was estimated at 25% (observed: 23%). After 0.5, 1 and 1.5 years of expectant management after the completion of the fertility workup, the average probability of conceiving naturally over the next year was estimated at 18% (observed: 15%), 14% (observed: 14%) and 12% (observed: 12%). Calibration plots showed good agreement between predicted chances and the observed fraction of ongoing pregnancy within risk groups. Discrimination was moderate with c statistics similar to those in the internal validation, ranging from 0.60 to 0.64. The range of predicted chances was sufficiently wide to distinguish between couples having a good and poor prognosis with a minimum of zero at all times and a maximum of 55% over the first year after the workup, which decreased to maxima of 43% after 0.5 years, 34% after 1 year and 29% after 1.5 years after the fertility workup.Limitations, Reasons For Caution: The model slightly overestimated the chances of conception by ~2-3% points on group level in the first-year post-fertility workup and after 0.5 years of expectant management, respectively. This is likely attributable to the fact that the exact dates of completion of the fertility workup for couples were missing and had to be estimated.Wider Implications Of the Findings: The van Eekelen model is a valid and robust tool that is ready to use in clinical practice to counsel couples with unexplained subfertility on their individualized chances of natural conception at various points in time, notably when couples return to the clinic after a period of unsuccessful expectant management.Study Funding/competing Interest(s): This work was supported by a Chief Scientist Office postdoctoral training fellowship in health services research and health of the public research (ref PDF/12/06). There are no conflicts of interest. [ABSTRACT FROM AUTHOR]

Study Question: What is the natural conception rate over the course of 12 months in couples with unexplained or mild male subfertility who are scheduled for fertility treatment and have a predicted unfavourable prognosis for natural conception?Summary Answer: The natural conception rate over the course of 12 months in couples who were allocated to treatment was estimated to be 24.5% (95% CI: 20-29%).What Is Known Already: After starting treatment, couples often perceive unsuccessful cycles as evidence of definitive failure even though they are still able to conceive naturally in between and after treatment. The magnitude of the natural conception rate for couples who chose to commence treatment is unknown, as is whether the calculated prognosis before commencing treatment is still applicable.Study Design, Size, Duration: We performed a secondary analysis of a randomized controlled trial including couples with unexplained or mild male subfertility and an unfavourable prognosis for natural conception. Couples were allocated to either three cycles IVF with single embryo transfer (SET), six cycles of IVF in a modified natural cycle (MNC) or six cycles of IUI with controlled ovarian hyperstimulation (IUI-COH). The detailed data collection in this trial allowed us to study the conception rates in periods that couples were not receiving treatment.Participants/materials, Settings, Methods: We split the dataset into periods during which couples were treated and periods during which they were not treated. Couples could conceive naturally in the periods before, in between and after treatment cycles. The outcome was ongoing pregnancy, thus natural conception rate refers to natural conception leading to ongoing pregnancy. We performed a Cox proportional hazards analysis with female age, duration of subfertility and a time-varying covariate with four categories: IVF-SET, IVF-MNC, IUI-COH and no treatment. We used this Cox model to estimate the natural conception rate over 12 months of no treatment.Main Results and the Role Of Chance: Out of 602 included couples, there were 342 ongoing pregnancies, of which 77 (23%) resulted from natural conception. The estimated natural conception rate over 12 months was 24.5% (95% CI: 20-29%) on cohort level. Estimated rates for female age varying between 18 and 38 years and duration of subfertility between 1 and 3 years ranged from 22 to 35%.Limitations, Reasons For Caution: We considered couples at risk for natural conception when not receiving treatment, whereas they might not have had periovulatory sexual intercourse. As couples were scheduled for treatment, it is possible that these couples were less inclined to try to conceive naturally, potentially leading to an underestimation of their natural conception rate if they kept trying to conceive.Wider Implications Of the Findings: Couples with unexplained subfertility who are about to start fertility treatment, still have about a one in four chance of ongoing pregnancy due to natural conception over 12 months. This information can add to the counselling of couples who commenced fertility treatment after failed cycles and to emphasize not to cease their natural attempts.Study Funding/competing Interest(s): The INeS trial was supported by a grant from ZonMW, the Dutch Organization for Health Research and Development (120620027), and a grant from Zorgverzekeraars Nederland, the Dutch association of health care insurers (09-003). The funders had no role in study design, collection, analysis and interpretation of the data. B.W.M. is supported by a NHMRC Practitioner Fellowship (GNT1082548). B.W.M. reports consultancy for ObsEva, Merck and Guerbet. No other potential conflicts of interest reported.Trial Registration Number: The INeS trial was registered at the Dutch trial registry (NTR 939). [ABSTRACT FROM AUTHOR]

Couples in whom the results of an initial fertility workup fail to identify the presence of any obvious barriers to conception are diagnosed with unexplained subfertility. Couples who have tried to conceive for a relatively short time have a good chance of natural conception and thus may not benefit from immediate access to ART. As fertility decreases over time, the main dilemma that clinicians and couples face is when to abandon an expectant approach in favour of active treatment. Several prognostic or predictive models have been used to try to discriminate between couples with high and low chances of conception but have been unable to compare individualized chances of conception associated with ART relative to chances of natural conception at various time points. These models are also unable to recalculate the chances of pregnancy at subsequent time points in those who return after a period of unsuccessful expectant management. In this paper, we discuss currently available models. We conclude that in order to provide accurate, individualized and dynamic fertility prognoses associated with and without treatment at different points in time, we need to develop, validate and update clinical prediction models which are fit for purpose. We suggest several steps to move the field forwards. [ABSTRACT FROM AUTHOR]

Study Question: How can we predict chances of natural conception at various time points in couples diagnosed with unexplained subfertility?Summary Answer: We developed a dynamic prediction model that can make repeated predictions over time for couples with unexplained subfertility that underwent a fertility workup at a fertility clinic.What Is Known Already: The most frequently used prediction model for natural conception (the 'Hunault model') estimates the probability of natural conception only once per couple, that is, after completion of the fertility workup. This model cannot be used for a second or third time for couples who wish to know their renewed chances after a certain period of expectant management.Study Design, Size, Duration: A prospective cohort studying the long-term follow-up of subfertile couples included in 38 centres in the Netherlands between January 2002 and February 2004. Couples with bilateral tubal occlusion, anovulation or a total motile sperm count <1 × 106 were excluded.Participants/materials, Setting, Methods: The primary endpoint was time to natural conception, leading to an ongoing pregnancy. Follow-up time was censored at the start of treatment or at the last date of contact. In developing the new dynamic prediction model, we used the same predictors as the Hunault model, i.e. female age, duration of subfertility, female subfertility being primary or secondary, sperm motility and referral status. The performance of the model was evaluated in terms of calibration and discrimination. Additionally, we assessed the utility of the model in terms of the variability of the calculated predictions.Main Results and the Role Of Chance: Of the 4999 couples in the cohort, 1053 (21%) women reached a natural conception leading to an ongoing pregnancy within a mean follow-up of 8 months (5th and 95th percentile: 1-21). Our newly developed dynamic prediction model estimated the median probability of conceiving in the first year after the completion of the fertility workup at 27%. For couples not yet pregnant after half a year, after one year and after one and a half years of expectant management, the median probability of conceiving over the next year was estimated at 20, 15 and 13%, respectively. The model performed fair in an internal validation. The prediction ranges were sufficiently broad to aid in counselling couples for at least two years after their fertility workup.Limitations, Reasons For Caution: The dynamic prediction model needs to be validated in an external population.Wider Implications Of the Findings: This dynamic prediction model allows reassessment of natural conception chances after various periods of unsuccessful expectant management. This gives valuable information to counsel couples with unexplained subfertility that are seen for a fertility workup.Study Funding/competing Interests: This study was facilitated by grant 945/12/002 from ZonMW, The Netherlands Organization for Health Research and Development, The Hague, The Netherlands. No competing interests. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Can mixture survival models help distinguish infertility from subfertility in couples with an unexplained unfulfilled child wish? SUMMARY ANSWER Mixture models estimated that 47% of the couples were infertile; female age and previous pregnancy were significantly related to infertility, whereas duration of child wish was associated with a longer time to pregnancy for subfertile couples. WHAT IS KNOWN ALREADY To differentiate between couples who require assisted conception and couples who still have good chances of natural, i.e. unassisted, conception, several prediction models of natural conception have been developed. Prognostic factors in these models are usually assessed by Cox proportional hazard models that cannot differentiate between couples with an unfulfilled child wish who are subfertile, i.e. have reduced ability to conceive naturally, and couples who are really infertile, i.e. are completely unable to conceive naturally. We evaluated whether a mixture survival model can make such a distinction. STUDY DESIGN, SIZE, DURATION Consecutive couples presenting at the fertility clinics of 38 centres in the Netherlands between January 2002 and February 2004 joined a prospective cohort study. Of the 7860 couples in the cohort, 3917 couples met our inclusion criteria. The median follow-up was 219 days, with a maximum of 5 years. PARTICIPANTS, SETTING, METHODS Couples had to present with an unexplained cause of an unfulfilled child wish. A mixture model was used to estimate the proportion of couples who were infertile and the time to pregnancy for the subfertile couples. MAIN RESULTS AND THE ROLE OF CHANCE During the follow-up, 794 couples conceived naturally. The mixture model estimated that 47% [95% confidence interval (CI): 33–56%] of couples were infertile, despite the absence of objective factors indicating a cause for infertility. Of the evaluated prognostic factors, female age, duration of child wish, previous pregnancy, semen quality, BMI and cycle length, female age [odds ratio (OR): 1.11, 95% CI: 1.03–1.19] and previous pregnancy (0.22, 95% CI: 0.07–0.67) were significant predictors of infertility. Among subfertile couples, a longer duration of a child wish (FFR: 0.72, 95% CI: 0.61–0.85) was a significant prognostic factor for time to pregnancy. In the Cox models, all variables except BMI were significant predictors of time to pregnancy. LIMITATIONS, REASONS FOR CAUTION The mixture model had limited power due to a low number of couples at the end of the follow-up period. Mixture model analyses on external, long-term follow-up data are necessary to validate our results. WIDER IMPLICATIONS OF THE FINDINGS Mixture models could be a useful tool in selecting couples who require assisted reproductive technology because the effects of prognostic factors can be subdivided into effects on the fraction of infertile couples and effects on the time to pregnancy for subfertile couples, which is not possible in conventional models. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by grant 945/12/002 from ZonMw, the Netherlands Organization for Health Research and Development, The Hague, the Netherlands. [ABSTRACT FROM AUTHOR]

BACKGROUND Prediction of natural conception in subfertile couples can help to differentiate between couples who should have immediate treatment and couples who can aim for natural conception for some time. Natural conception rates are often estimated using standard techniques such as Kaplan–Meier or Cox proportional hazard models. These estimates can be biased by incorrect handling of data from women who start assisted reproductive technology therapy before the end of the follow-up period. This paper discusses the validity and the impact of the assumption of non-informative censoring as used in the Kaplan–Meier and Cox models. METHODS In a cohort of 5360 subfertile couples with suspected tubal pathology, the probability of natural conception and the prognostic value of additional tests for tubal pathology were estimated using traditional methods and with a competing risks analysis. RESULTS The estimated probability of natural conception within 3 years was almost 2-fold higher when assuming non-informative censoring compared with the competing risks model, 41 versus 22%. The prognostic value of tests was more conservative using the competing risks model than with the traditional methods, the fecundity rate ratio for Chlamydia antibody testing was 0.72 versus 0.67, for hysterosalpingography, 0.83 versus 0.71 and for diagnostic laparoscopy, 0.89 versus 0.74. CONCLUSIONS Given the improbable validity of the non-informative censoring assumption, the predictions of natural conception and of the prognostic value of tests are likely to be overestimated by the traditional analytic methods. We suggest the use of competing risks models as an alternative, more conservative, form of analysis when predicting natural conception and evaluating prognostic fertility tests. [ABSTRACT FROM AUTHOR]

Abstract Research question Hysterosalpingography (HSG) with an oil-based contrast has been shown to increase ongoing pregnancy rates compared with HSG with water-based contrast, but it remains unclear if an effect of HSG occurs compared with no HSG. Design A secondary data-analysis of a prospective cohort study among 4556 couples that presented with unexplained subfertility in 38 clinics in the Netherlands between January 2002 and December 2004. A time-varying Cox regression with inverse probability of treatment weighing was used to analyse ongoing pregnancy rates in women after undergoing the HSG procedure (with the use of either water- or oil-based contrast media) compared with women who did not undergo HSG. Results The probability of natural conception within 24 months after first presentation at the fertility clinic was increased after HSG, regardless of the type of contrast medium used, compared with no HSG (adjusted hazard ratio 1.48, 95% CI 1.26 to 1.73, corresponding to an absolute increase in 6-month pregnancy rate of +6%). When this analysis was limited to HSGs that were made with water-contrast, the treatment effect remained (adjusted hazard ratio 1.40, 95% CI 1.16 to 1.70). Conclusions HSG increases the ongoing pregnancy rate of couples with unexplained subfertility compared with no HSG, regardless of the contrast medium used. Results need to be validated in future, preferably randomized, studies. [ABSTRACT FROM AUTHOR]