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Objective: To evaluate the use of cryopreserved ovarian tissue in the Danish fertility preservation cohort., Design: Retrospective cohort study., Setting: University hospitals and fertility clinics., Patient(s): Ovarian tissue cryopreservation (OTC) was performed for 1,186 Danish girls and women from 1999-2020, of whom 117 subsequently underwent ovarian tissue transplantation (OTT). Subgroup 1 included 759 patients with a follow-up period of >5 years. Out of these, OTT rates were further analyzed for those patients who were alive and aged >24 years in July 2020 (subgroup 2; n = 554)., Intervention(s): OTC and OTT., Main Outcome Measure(s): OTT, death, donation of tissue., Result(s): In subgroup 1, 14% of the patients had undergone OTT, 18% had died, 9% had donated their tissue for research, and 59% still had their tissue stored. In subgroup 2, 19% had undergone OTT and for most diagnoses the OTT rates ranged from 15% to 22% with benign hematologic diseases having the highest OTT rate (35%). On the basis of the entire cohort, stratified age analysis indicated that women aged ≥30 years at OTC were more likely to return for OTT than women aged 18-29 years at OTC; mean storage times were 3.7 and 3.6 years, respectively. Only 4% of the girls aged <18 years at OTC had undergone OTT., Conclusion(s): The OTT rates depended on the diagnosis, age at OTC, and follow-up time. Specific criteria are needed for reporting and comparing OTT rates. Six out of 10 patients still had their cryopreserved tissue stored and longer follow-up is needed, especially for younger girls., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Transplantation of ovarian tissue is a valuable method to rescue mouse strains with fertility problems and to revitalize archived strains. The purpose of this study was to investigate the effect of (i) different sizes of transplanted ovary pieces on reproductive outcome, (ii) use of immunodeficient recipients to overcome the limitation of histocompatibility, and (iii) to compare different protocols for cryopreservation of ovarian tissue., Methods: Halves, quarters, and eights of mouse ovaries were transplanted. Half ovaries from B6 donors were transferred into immunodeficient mice. Halves of ovaries were frozen according to four different protocols, thawed and transferred., Results: Pregnancy rate after transplantation of ovarian tissue was high (90-100%) independent of the transplant size. Although, the average litter size was significantly lower for recipients of quarters and eights (4.4 and 4.6 vs. 6.5), the total number of offspring produced per donor ovary was higher compared with recipients of halves. Pregnancy rate of immunodeficient recipients was 40% (mean 4.7 offspring per litter). All four cryopreservation protocols used were able to preserve functionality of the ovarian tissue., Conclusions: Transplantation of ovarian tissue smaller than halves resulted in reduced litter sizes. The distribution of ovarian tissue of one donor female to 4 or 8 recipients will therefore yield in a higher total number of offspring in a certain time period. The use of immunodeficient recipients is an option for non-histocompatible donors. Cryopreservation of ovarian tissue is generally feasible but the function of frozen-thawed ovary halves after transplantation differs depending on the freezing protocol used.

Background: Fertility preservation by whole ovary cryopreservation and transplantation (WOCP&TP) with vascular anastomosis requires successful cryopreservation. In this study, we investigated the possibility of restoring ovarian function and natural fertility after WOCP&TP in a premature ovarian insufficiency (POI) rat model. The influence of cryopreservation on the offspring of rats following WOCP&TP was also explored., Method: Rats aged 8-10 weeks were used as donors and recipients for allotransplantation. Fifteen rat whole ovaries were divided into three groups: the optimized group, the conventional group, and the fresh group. Different perfusion modes were used before cryopreservation and after thawing. Whole ovaries were observed by morphologic analysis, immunohistochemical staining, and transferase-mediated deoxyuridine triphosphate nick end-labeling assay. Ovarian function and fertility after WOCP&TP were then observed in 25 cyclophosphamide-induced POI rats for 8 months. Ovarian function was assessed by vaginal smears and blood hormone levels. Fertility restoration was quantified as the live birth rate after mating. The filial generation of rats was mated at 8-10 weeks of age. Offspring were observed for birth defect., Results: Histological evaluation demonstrated intact morphology of follicles in all groups, with 77.6% of the total number of follicles identified as intact in the optimized group. The apoptotic rates of ovarian cells in the optimized group were significantly lower than that in the conventional group. Of the 20 live POI rats, 14 (70%) began to recover ovarian function after 2 weeks of transplantation, with normal hormone levels achieved 4 weeks after transplantation. Four of 14 rats were pregnant and delivered live offspring. One rat had a second pregnancy and delivered a second litter of live offspring. When the offspring matured, they were mated, and second and third generations of rats were born. All offspring had no abnormalities in appearance., Conclusions: High rates of restoration of ovarian function and natural fertility with multiple generations of offspring were obtained following WOCP&TP in a cyclophosphamide-induced POI rat model by utilizing optimized perfusion. Cryopreservation did not affect the viability of successive generations.

Objective: To compare the efficacy of oocyte vitrification (OV) with that of ovarian cortex cryopreservation and transplantation (OCT) in women undergoing gonadotoxic treatments., Design: Prospective observational cohort study., Setting: Not applicable., Patient(s): Candidates for chemo-/radiotherapy who joined our fertility preservation (FP) program were included in this study between 2005 and 2015. One cohort included 1,024 patients undergoing OV; the other cohort included 800 patients undergoing OCT., Intervention(s): OV using the cryotop device and OCT using a slow freezing protocol., Main Outcome Measure(s): Live-birth rate (LBR) and clinical pregnancy rate (CPR)., Result(s): Basal antimüllerian hormone levels of the patients revealed no differences in ovarian reserve before FP (OV, 11.6 pM [5.4-24.7]; OCT, 11.8 pM [6.4-21.9]). In the OV cohort, 49 patients used the vitrified oocytes after a mean storage time of 3.9 years. In the OCT cohort, 44 sought pregnancy after a mean storage time of 5.5 years. A trend toward higher CPR and LBR (per patient) was observed in the OV group (risk ratio [RR CPR ], 1.31 [95% confidence interval, 0.90-1.92]; RR LBR 1.39 [95% confidence interval, 0.95-2.03]), although differences were not statistically significant. In the OCT group, 46.7% of pregnancies occurred spontaneously and no pregnancy was achieved when the tissue was harvested beyond the age of 36 years. All patients except three undergoing OCT resumed or improved endocrine ovarian function., Conclusion(s): Although we observed a trend toward higher LBR after OV, OCT is a very effective method to preserve fertility, allows for natural pregnancy, and restores ovarian function. In clinical scenarios where OV is not feasible, OCT remains the FP technique of choice and should no longer be considered experimental., (Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

The observation of pups born from recipient and donor mice after ovariectomy followed by ovarian transplant poses the interesting possibility of an extraovarian source of oocytes. However, whether mammalian adult oocytes reside in extragonadal tissues remains elusive. Using transgenic fluorescent reporter mice and transplantation surgeries, we demonstrate the presence of both donor- and recipient-derived corpora lutea and recovery of both donor- and recipient-derived offspring from ovariectomized mice after transplantation of donor ovaries. A potential region for extraovarian oocytes is the hilum, a ligament-like structure between the ovary and the reproductive tract. Immunofluorescent confocal microscopy of mouse ovaries and reproductive tracts revealed that a population of primordial follicles resides outside the ovary within the hilum. Ovariectomy-only controls confirmed that oocytes remain in the recipient hilum after surgery. These results provide evidence that the hilum is a reserve source of follicles, which likely return to the ovary for maturation and ovulation. By identifying a new follicle reservoir, our study addresses a long-standing question in reproductive biology and contributes to new conceptual knowledge about ovarian function and fertility., (© The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please journals.permissions@oup.com.)

This review focuses on advances in the field of fertility preservation achieved over the past few decades. The main purpose of fertility preservation is to help young cancer survivors retain their fertility by restoring either their ability to procreate or simply their reproductive endocrine function. Although different options are available in this regard, successful fertility preservation is yet to reach its full potential. Herein, we review the most significant work conducted over the past five decades and present new methodologies., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

With the increasing numbers of survivors of cancer in young people, future fertility and ovarian function are important considerations that should be discussed before treatment commences. Some young people, by nature of the treatment they will receive, are at high risk of premature ovarian insufficiency and infertility. For them, ovarian tissue cryopreservation (OTC) is one approach to fertility preservation that remains both invasive and for young patients experimental. There are important ethical and consent issues that need to be explored and accepted before OTC can be considered established in children with cancer. In this review we have discussed a framework for patient selection which has been shown to be effective in identifying those patients at high risk of premature ovarian insufficiency and who can be offered OTC safely., (Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Oocyte and ovarian tissue cryopreservation represents one of the most important advances in the field of reproductive medicine and biology. Preserving a woman's potential for becoming a genetic mother is now possible for numerous diseases that could impair female fertility either by themselves or as a result of their treatments. However, female fertility preservation is still at the pioneering level and is thus often considered an experimental treatment either from a technical standpoint or in the clinical situation in which it is discussed. As a consequence, many ethics issues are raised with fertility preservation treatment in infants, adolescents, and young women., (Copyright © 2016. Published by Elsevier Inc.)

Premature ovarian insufficiency is a relatively rare condition that can appear early in life. In a non-negligible number of cases the ovarian dysfunction results from genetic diseases. Turner syndrome (TS), the most common sex chromosome abnormality in females, is associated with an inevitable premature exhaustion of the follicular stockpile. The possible or probable infertility is a major concern for TS patients and their parents, and physicians are often asked about possible options to preserve fertility. Unfortunately, there are no recommendations on fertility preservation in this group. The severely reduced follicle pool even during prepubertal life represents the major limit for fertility preservation and is the root of numerous questions regarding the competence of gametes or ovarian tissue crybanked. In addition, patients suffering from TS show higher than usual rates of spontaneous abortion, fetal anomaly, and maternal morbidity and mortality, which should be considered at the time of fertility preservation and before reutilization of the cryopreserved gametes. Apart from fulfillment of the desire of becoming genetic parents, TS patients may be potential candidates for egg donation, gestational surrogacy, and adoption. The present review discusses the different options for preserving female fertility in TS and the ethical questions raised by these approaches., (Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To develop a novel molecular panel of markers to detect breast cancer (BC) disseminated malignant cells in ovarian tissue, and to improve the safety of ovarian tissue transplantation., Design: Experimental study., Setting: University hospital., Patient(s): Ten ovarian biopsies from healthy patients, 13 biopsies with diagnosed BC metastasis, and 4 biopsies from primary BC tumor for designing a diagnostic panel of BC cell contamination; 60 ovarian biopsies from BC patients undergoing fertility preservation for validating the panel., Animal(s): Female nude mice., Intervention(s): A novel panel for BC malignant cell detection by reverse-transcription polymerase chain reaction (RT-PCR), inmmunohistochemical analysis, in vitro invasion assay and xenotransplantation assayed in ovarian tissue from BC patients., Main Outcome Measure(s): Expression of GCDFP15, MGB1, SBEM, MUC1, WT-1, and NY-BR-01, selected as markers, assessed by quantitative RT-PCR in samples with confirmed BC metastasis. The most sensitive markers were confirmed by immunohistochemistry, and tested in vitro and in vivo., Result(s): GCDFP15, MGB1, and SBEM were the most sensitive and specific markers to detect BC metastatic cells when at least one was expressed by quantitative RT-PCR. The panel was validated in 60 patients and confirmed in an in vitro invasion assay, where no invasive cells were observed. Samples negative for BC cells cannot develop disease when xenografted., Conclusion(s): GCDFP15, MGB1, and SBEM were the most sensitive molecules to create a diagnostic panel for BC malignant cell contamination, which may make ovarian tissue cryopreservation and transplantation a safe technique for fertility preservation in BC patients., (Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Study Question: What are the results of transplanting cryopreserved ovarian tissue?, Summary Answer: The transplanted ovarian tissue can last up to 10 years, with no relapses following the 53 transplantations, and the chance of a successful pregnancy is currently around one in three for those with a pregnancy-wish., What Is Known Already: Cryopreservation of ovarian tissue is now gaining ground as a valid method for fertility preservation. More than 36 children worldwide have now been born following this procedure., Study Design, Size, Duration: This is a retrospective cohort study of 41 women who had thawed ovarian tissue transplanted 53 times over a period of 10 years, including 1 patient who was lost to follow-up., Participants/materials, Setting, Methods: The 41 Danish women, who had in total 53 transplantations, were followed for ovarian function and fertility outcome. Safety was assessed by monitoring relapse in cancer survivors., Main Results, and the Role of Chance: Among 32 women with a pregnancy-wish, 10 (31%) had a child/children (14 children in total); this included 1 woman with a third trimester on-going pregnancy. In addition, two legal abortions and one second trimester miscarriage occurred. A total of 24 clinical pregnancies were established in the 32 women with a pregnancy-wish. The tissue remained functional for close to 10 years in some cases and lasted only a short period in others. Three relapses occurred but were unlikely to be due to the transplanted tissue., Limitations, Reasons for Caution: Self-report through questionnaires with only in-one hospital formalised follow-up of transplanted patients could result in unreported miscarriages. The longevity of the tissue may vary by few months compared with those reported because some patients simply could not remember the date when the tissue became non-functional., Wider Implications of the Findings: Cryopreservation of ovarian tissue is likely to become integrated into the treatment of young women, with cancer, who run a risk of losing their fertility. The full functional lifespan of grafts is still being evaluated, because many of the transplanted women have continued to maintain ovarian activity. Some of our first cases have had tissue functioning for ∼ 10 years., (© The Author 2015. 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.)

Cryopreservation of eggs or ovarian tissue to preserve fertility for patients with cancer has been studied since 1994 with R G Gosden's paper describing restoration of fertility in oophorectomised sheep, and for decades previously by others in smaller mammals. Clinically this approach has shown great success. Many healthy children have been born from eggs cryopreserved with the Kuwayama egg vitrification technique for non-medical (social) indications, but until now very few patients with cancer have achieved pregnancy with cryopreserved eggs. Often, oncologists do not wish to delay cancer treatment while the patient goes through multiple ovarian stimulation cycles to retrieve eggs, and the patient can only start using the oocytes after full recovery from cancer. Ovarian stimulation and egg retrieval is not a barrier for patients without cancer who wish to delay childbearing, which makes oocyte cryopreservation increasingly popular to overcome an age-related decline in fertility. Cryopreservation of ovarian tissue is an option if egg cryopreservation is ruled out. More than 35 babies have been born so far with cryopreserved ovarian tissue in patients with cancer who have had a complete return of hormonal function, and fertility to baseline. Both egg and ovarian tissue cryopreservation might be ready for application to the preservation of fertility not only in patients with cancer but also in countering the increasing incidence of age-related decline in female fertility., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Study Question: Is it possible to restore ovarian function and natural fertility following the cryopreservation and autotransplantation of whole ovaries, complete with vascular pedicle, in adult females from a large monovulatory animal model species (i.e. sheep)?, Summary Answer: Full (100%) restoration of acute ovarian function and high rates of natural fertility (pregnancy rate 64%; live birth rate 29%), with multiple live births, were obtained following whole ovary cryopreservation and autotransplantation (WOCP&TP) of adult sheep ovaries utilizing optimized cryopreservation and post-operative anti-coagulant regimes., What Is Known Already: Fertility preservation by WOCP&TP requires successful cryopreservation of both the ovary and its vascular supply. Previous work has indicated detrimental effects of WOCP&TP on the ovarian follicle population. Recent experiments suggest that these deleterious effects can be attributed to an acute loss of vascular patency due to clot formation induced by damage to ovarian arterial endothelial cells., Study Design, Size, Duration: Study 1 (2010-2011; N = 16) examined the effect of post-thaw perfusion of survival factors (angiogenic, antioxidant, anti-apoptotic; n = 7-8) and treatment with aspirin (pre-operative versus pre- and post-operative (n = 7-9)) on the restoration of ovarian function for 3 months after WOCP&TP. Study 2 (2011-2012; N = 16) examined the effect of cryoprotectant (CPA) perfusion time (10 versus 60 min; n = 16) and pre- and post-operative treatment with aspirin in combination with enoxaparine (Clexane(®); n = 8) or eptifibatide (Integrilin(®); n = 8) on ovarian function and fertility 11-23 months after WOCP&TP., Participants/materials, Setting, Methods: Both studies utilized mature, parous, Greyface ewes aged 3-6 years and weighing 50-75 kg. Restoration of ovarian function was monitored by bi-weekly blood sampling and display of behavioural oestrus. Blood samples were assayed for gonadotrophins, progesterone, anti-Müllerian Hormone and inhibin A. Fertility restoration in Study 2 was quantified by pregnancy rate after a 3 month fertile mating period and was confirmed by ultrasound, hormonal monitoring and live birth. Ovarian function was assessed at sacrifice by ovarian appearance and vascular patency (Doppler ultrasound) and by follicular histology., Main Results and the Role of Chance: In Study 1, survival factors were found to have no benefit, but the inclusion of pre-operative aspirin resulted in four ewes showing acute restoration of ovarian function within 3 weeks and a further six ewes showing partial restoration. The addition of post-operative aspirin alone had no clear benefit. In Study 2, combination of aspirin with additional post-operative anti-coagulants resulted in total acute restoration of ovarian function in 14/14 ewes within 3 weeks of WOCP&TP, with 9/14 ewes becoming pregnant and 4/14 giving birth to a total of seven normal lambs. There was no difference between anti-coagulants in terms of restoration of reproductive function and fertility. In contrast, the duration of CPA perfusion was highly significant with a 60 min perfusion resulting in ovaries of normal appearance and function with high rates of primordial follicle survival (70%) and an abundant blood supply, whereas ovaries perfused for 10 min had either resorbed completely and were vestigial (7/14) or were markedly smaller (P < 0.01). It is concluded that both the degree of CPA penetration and the maintenance of post-operative vascular patency are critical determinants of the success of WOCP&TP., Limitations, Reasons for Caution: Before application of this technology to fertility preservation patients, it will be critical to optimize the CPA perfusion time for different sized human ovaries, determine the optimum period and level of anti-coagulant therapy, and confirm the normality of offspring derived from this procedure., Wider Implications of the Findings: This technology holds promise for the preservation of fertility in women. It could also potentially be applied to the cryopreservation of other reproductive or even major organs (kidneys) where there are considerable difficulties in storing donated tissue., Study Funding/competing Interests: Funding was received from the Medical Research Council, University of Nottingham. The authors confirm that they have no conflict of interest in relation to this work., (© The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.)

Background: Cryopreservation of the ovarian tissue has shown promising results. However, there remain controversial issues such as the short half-life of grafts. In this aspect, there are some evidences that preconditioning the ovarian tissue before transplantation is beneficial., Objective: To determine the effect of hypoxic preconditioning in vitro on ovarian tissue prior to transplantation., Methods: Eighteen female adult Wistar rats, were sorted into three experimental groups. Ovaries were maintained in DMEM low glucose serum free at 37°C with 5% CO2, at atmospheric oxigen concentration (normoxia) or 1% O2 (hypoxia) for 16 hours. Oxigen concentration was determined by injection of nitrogen in the incubator. Animals submitted to ovarian transplantation immediately after oophorectomy were the Control Group (C). After this, the ovaries were implanted in the retroperitoneum with nonabsorbable suture and animals evaluated for thirty days after transplantation. Beginning on postoperative (PO) day 11, a daily collection of vaginal smear was carried out. Analyses comprised morphological, morphometric (counting ovarian follicles and corpora lutea) and immunohistochemistry for cleaved caspase-3 (apoptosis)., Results: In normoxia and control groups all animals recovered their estrous cycles, while in the hypoxia group, two animals did not ovulate but, among those which did, resumption took longer than in the other groups (p < 0.05). The number of ovarian follicles and corpora lutea decreased significantly in the hypoxia group when compared to the other two groups (p < 0.001) and apoptosis was increased in the few ovarian follicles which remained viable (p < 0.001)., Conclusion: The hypoxic preconditioning in vitro was not beneficial to the graft and worsened their viability, compromising its functionality or delaying the return of this.

As a result of advances in medical treatment, almost 80% of children who are diagnosed with cancer survive long-term. The adverse consequences of cancer treatments include impaired puberty and fertility. In prepubertal girls, the only therapeutic option is the cryopreservation of an ovary. To date, a dozen births have been reported after reimplantation of cryopreserved mature ovaries. To analyze ovarian function after immature grafts, we performed ovarian grafting in a ewe model. Fresh or cryopreserved ovaries from immature ewes were autografted in prepubertal or adult ewes. Cyclic hormonal activity was recovered 3 mo after grafting. Histological analysis demonstrated the presence of all follicle populations and corpora lutea not affected by cryopreservation. After 3 reproductive seasons, births had been observed in all groups, and the follicle-stimulating hormone status was under the limit, which indicated an exhausted ovary. As an indicator of potential imprinting default, the methylation status of the Igf2r gene was analyzed and did not show significant alteration compared with that of nonmanipulated animals. Taken together, these results demonstrate that immature ovarian grafting is able to restore spontaneous puberty and fertility and could guide the reimplantation of immature cortex in women.

Objective: To evaluate the genetic safety of vitrification on the methylation imprints and the development and fertility potential of prepubertal mouse ovaries., Design: Experimental animal study., Setting: University-based fertility center., Animal(s): Institute of Cancer Research (ICR) 10-day-old female mice, 10-week-old adult female mice, and 12-week-old adult male mice., Intervention(s): Vitrification of juvenile mouse ovaries was performed using ED20 and EG5.5/30 solutions followed by retrieval of fresh and vitrified-warmed germinal vesicle (GV) oocytes for Snrpn differentially methylated regions (DMR) methylation analyses, collection of mature oocytes from superovulated ovarian grafts, in vitro fertility(IVF), and early embryonic development after heterotopic allotransplantation., Main Outcome Measure(s): Analysis of methylation status of Snrpn-DMR, percentage of fertilization, and blastocysts formation., Result(s): Methylation status of Snrpn-DMR from vitrified-warmed GV oocytes did not show significant alteration compared with that of controls, although a significant reduction of viable oocytes was observed. Puberty as well as endocrine function was restored, and no significant difference was shown in number of follicles, percentage of mice retaining fertility, and blastocyst formation among three groups., Conclusion(s): Our study proved that vitrification of prepubertal mouse ovaries did not alter the methylation profile of Snrpn-DMR and subsequent allotransplantation; IVF could restore the development and fertility potential., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)

Objectives: Fertility preservation is not only important for malignant diseases but should also be offered to patients with autoimmune diseases (AID) like vasculitides, prior to cyclophosphamide therapy. No recommendations are available for patients with AID., Methods: Analysis from the Fertiprotekt registry of all female patients with age <40 and the diagnosis of a vasculitis. The number of counselled patients, their diagnosis and age, the number of children before the start of therapy as well as the fertility preservation treatment chosen were evaluated., Results: From January 2007 to November 2011, 47 patients with the diagnosis AID were counselled at 17 of the 69 Fertiprotekt centres. 80.9% decided for at least one of the offered preservation methods. Ovarian cryopreservation was performed in 6 patients, 36 patients opted for GnRH-analogue treatment. Two patients decided for a stimulation therapy for cryopreservation of oocytes., Conclusions: Regarding the experiences from the registry and the literature gonadotropin releasing hormone analogues are evaluated best and recommended to most of the patients with AID. Cryoconservation of ovarian tissue is a promising option. Stimulation for oocyte cryopreservation can be offered to patients with vasculitis. A combination of the methods might have the biggest preservative effect.

Endometriosis is one of the most frequently encountered benign diseases in gynecology. Complete resolution of endometriosis is not yet possible, but therapy has essentially three main objectives: (1) to preserve and improve fertility, (2) to reduce pain, and (3) to delay recurrence for as long as possible. The aim of this paper is to focus on fertility preservation in women with severe endometriosis. In moderate and severe endometriosis, a medico-surgical approach remains the gold standard, but more and more papers are reporting a low ovarian reserve after laparoscopic cystectomy for endometriomas. Indeed, very frequently, normal ovarian tissue is excised together with the endometrioma wall. Ovarian surgery in endometriosis patients should therefore be performed by experienced surgeons in order to both preserve and improve fertility. Preservation of ovarian tissue should be considered in all patients at serious risk of future fertility impairment, particularly before any treatment likely to result in ovarian endometriosis recurrence and/or premature ovarian failure.

Purpose: Fertility preservation methods are playing an increasing role in women up to the age of 40 years because of rising survival rates in those affected by cancer. However, balanced practical recommendations concerning all relevant fertility preservation, to support doctors in counselling and treating patients, are still rare., Methods: These recommendations were prepared by the network FertiPROTEKT ( http://www.fertiprotect.eu ), a collaboration of around 70 centres in Germany, Switzerland and Austria. The recommendations were developed by specialists in reproductive medicine, reproductive biology and oncology, which gave a comprehensive overview of all named techniques as well as their benefits and risks. Furthermore, practice-orientated recommendations for the individual use of fertility preservation methods for various indications such as breast cancer, Hodgkin's lymphoma and borderline ovarian tumours are given., Results: Various options such as ovarian stimulation and cryopreservation of unfertilised or fertilised oocytes, cryopreservation and transplantation of ovarian tissue, GnRH-agonist administration and transposition of the ovaries can be offered. All the techniques can be performed alone or in combination within a maximum of 2 weeks with low risk and different success rates., Conclusions: Fertility preservation in women has become an option with realistic chances to become pregnant after cytotoxic therapies. The information provided allows a well balanced and realistic counselling and treatment.

Several options are currently available for the preservation of fertility in cancer patients: embryo cryopreservation, oocyte cryopreservation or ovarian tissue cryopreservation. The choice of the most suitable strategy for preserving fertility depends on different parameters: the type and timing of chemotherapy, the type of cancer, the patient's age and the partner status. Cryopreservation of ovarian tissue is the only option available for prepubertal girls and woman who cannot delay the start of chemotherapy. So far, 15 live births have been obtained after orthotopic transplantation of cryopreserved ovarian tissue., (© 2011 Blackwell Publishing Ltd.)

Objective: To evaluate the function of human ovarian transplants., Design: Follow a series of fresh ovarian transplants for up to 5 years, and compare fresh and frozen ovarian tissue transplantation., Setting: Tertiary referral community hospital., Patient(s): Nine women with premature ovarian failure who received an ovary donated from a monozygotic twin sibling, and 16 young cancer patients undergoing ovarian cryopreservation. Two of the transplant recipients were cancer survivors rendered sterile by their therapy., Intervention(s): Fresh ovary transplantation between monozygotic twin sisters, as well as transplantation of previously frozen ovarian tissue, and study of cryopreserved tissue in cancer patients., Main Outcome Measure(s): Return of normal menstrual cycling, hormone levels, pregnancy, healthy babies, duration of transplant function, and ovarian tissue evaluation., Result(s): Normal serum FSH and regular menstrual cycles returned by 5 months after surgery in all cases, both fresh and frozen. Fourteen spontaneous pregnancies were established leading to eight healthy live births and two healthy ongoing conceptions. All three frozen tissue transplants conceived spontaneously, one delivered, and two were ongoing. Oocyte survival with slow freezing was 42% and after vitrification 89%., Conclusion(s): Ovarian transplantation in humans is a robust procedure, even after cryopreservation, and vitrification might prove to be more effective than slow freezing., (Copyright © 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Background: Transplantation of the uterus has been suggested as a treatment of uterine factor infertility. This study investigates whether the sheep uterus can resume its capacity to harbour normal pregnancies after autotransplantation by vascular anastomosis., Methods: From 14 ewes, the uterus, excluding one uterine horn, was isolated along with its oviduct and ovary and preserved ex vivo and then transplanted back with end-to-side anastomosis of the vessels of the graft to the external iliac vessels. After recovery, the ewes underwent surgical examination and serum progesterone measurements to ascertain healing and ovarian activity. Afterwards, five autotransplanted and five control ewes were placed with a ram for mating. Caesarean sections were performed before the estimated term of pregnancy and data on fetal measures were compared., Results: Of the 14 ewes, seven survived surgery with ovarian activity intact and grafts showing normal appearance. Mating occurred in four of five transplanted ewes and in five out of five controls, and three transplanted animals and five control animals conceived. In one transplanted ewe, torsion of the uterus was observed after spontaneous initiation of labour. Foeti from transplanted mothers were comparable in size to those of controls., Conclusions: Despite the encountered complications, this is the first report to demonstrate fertility and pregnancies going to term after autotransplantation of the uterus in an animal of a comparable size to the human.

Background: Techniques for uterus transplantation (UTx) have been developed in rodent/domestic animals towards future clinical introduction of UTx to treat uterine factor infertility. The aim of this study was to extend the UTx research into a non-human primate species by developing surgical techniques for uterus retrieval and transplantation in the baboon., Methods: Female baboons (n = 15) underwent surgery, with the initial five animals used for studies of pelvic vascular anatomy. Retrieval surgery included isolation of the ovarian veins and the uterine arteries together with the anterior branches of the internal iliacs. The utero-tubal-ovarian specimen was removed, flushed and kept ex vivo for 2 h when the two arterial ends and two venous ends were anastomosed side-to-side to construct one arterial and one venous end. These were, at auto-transplantation, anastomosed end-to-side to the external iliacs and the animals (n = 10) were evaluated concerning cyclicity and later by laparoscopy/laparotomy., Results: The total duration of organ retrieval, backtable preparation and transplantation was around 6 h with an overall ischaemic time of the specimen of about 3 h. One animal died due to cardiomyopathy. Five out of the nine surviving animals resumed cyclicity, as a sign of re-established ovarian function. Only two out of these five animals exhibited resumed menstruation, indicating re-established ovarian and uterine function. Laparoscopy confirmed normal-sized uteri in these two animals., Conclusions: This study demonstrates the feasibility of UTx by vascular anastomosis in a non-human primate species. The low success rate demonstrates the complexity involved in UTx surgery and the need for further methodological developments.

Transgenic mice are useful tools for studying gene function and regulation but can be difficult to successfully breed. To 'rescue' transgenic lines that are difficult to propagate, researchers use a variety of techniques. One method is ovarian transplant, in which researchers remove ovaries from a donor transgenic mouse, cryopreserve the ovarian tissue, transplant this tissue into histocompatible female mice and breed these recipient females. Though it is a useful technique, cryopreservation can potentially damage ovarian tissue, which could reduce fertility. In this article, the authors describe how they carried out ovarian transplants without cryopreservation to rescue a line of transgenic C57BL/6 mice. Other researchers who have experience with mouse reproductive surgery should be able to use this technique to rescue infertile transgenic lines of mice.

Worldwide eight children have been born as a result of transplanting frozen/thawed ovarian tissue. Two of these children were born in Denmark following transport of the ovarian tissue for a period of 5 h prior to cryopreservation. One of these women, who was originally transplanted with six pieces of ovarian cortex, after having experienced a period of menopause has now conceived again following natural conception. She gave birth to a healthy girl on 23 September 2008 and is therefore the first woman in the world to have had two children, from separate pregnancies, born as a result of transplanting frozen/thawed ovarian tissue. This result encourages further development of cryopreservation of ovarian tissue for fertility preservation as a clinical procedure for girls and young women facing gonadotoxic treatment.

Transplantation of cryopreserved tissue from patients with cancer may carry the risk of reactivation or redissemination of micrometastases. This prospective study was conducted to evaluate the potential involvement of micrometastases in ovarian tissue in cancer patients. Ovarian biopsies were collected from patients who underwent ovarian tissue cryopreservation, in our IVF unit before chemotherapy between 2000 and 2008. Indications for cryopreservation included breast cancer (n=13), osteosarcoma (n=13), hematologic malignancies (n=13), uterine cervix carcinoma (n=2), endometrial carcinoma (n=1), colon cancer (n=1), and brain medulloblastoma (n=1). The samples were stained with hematoxylin and eosin, and examined histologically. Immunoperoxidase broad-spectrum cytokeratin staining was also performed on specimens from breast cancer patients. There were 44 patients (age range 5-40 yr) who yielded 40 specimens. No gross pathologic involvement was observed, and the histologic examination revealed normal histology with no evidence of metastases. Our findings showed that for the purpose of considering ovarian tissue cryopreservation in cancer patients, the likelihood of microscopic metastases within ovaries of normal appearance is apparently very low. Clarification of the actual risk of ovarian involvement and any subsequent risk of micrometastases and tumor reimplantation requires further investigation.

Objective: To present a combination of ovarian tissue and oocyte cryopreservation as an effective strategy for achieving pregnancy in a breast cancer patient., Design: Case report., Setting: Tertiary care university-affiliated hospital, tissue bank, and infertility clinic., Patient(s): A 36-year-old patient diagnosed with atypical medullar breast cancer and negative for estrogen, P, and HER2 receptors underwent ovarian tissue cryopreservation before receiving chemotherapy and radiotherapy., Intervention(s): Laparoscopic ovarian cortex extraction, ovarian tissue cryopreservation, ovarian tissue thawing and transplantation, controlled ovarian stimulation (COS), oocyte retrieval, vitrification and IVF, and embryo culture and replacement., Main Outcome Measure(s): Resumption of spontaneous ovarian function after transplantation, response to COS, oocyte vitrification, IVF, pregnancy, and delivery., Result(s): Menses occurred 63 days after transplantation. Sixteen mature oocytes were obtained in four COS procedures. All vitrified oocytes survived warming, and 77.7% were fertilized. Two day 3 embryos were replaced, and two healthy boys were born at 34 weeks., Conclusion(s): Ovarian tissue cryopreservation and grafting preserves fertility. Simultaneous oocyte vitrification increases the success of assisted reproductive technology in poor-prognosis patients and avoids the consequences of the short lifespan of the transplanted tissue., (Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

A series of monozygotic (MZ) twin pairs discordant for premature ovarian failure presented an unusual opportunity to study ovarian transplantation. Ten MZ twin pairs requested ovarian transplantation and nine have undergone transplantation with cryopreservation of spare tissue. Eight had a fresh cortical tissue transplant, one of whom received a second frozen-thawed transplant after the first ceased functioning at 3 years. One had a fresh microvascular transplant. All recipients reinitiated ovulatory menstrual cycles and normal day 3 serum follicle-stimulating hormone levels by 77 to 142 days. Seven have already conceived naturally (three twice). Currently, seven healthy infants have been delivered out of 10 pregnancies. The oldest transplant ceased functioning by 3 years, but then she conceived again after a frozen-thawed secondary transplant. There was no apparent difference in return of ovarian function between the nine fresh ovarian grafts and the one frozen graft. Ovarian transplantation appears to restore ovulatory function robustly. Ten pregnancies, leading to seven healthy infants, including one after cryopreservation, bode well for application to fertility preservation., (Thieme Medical Publishers.)

Breast cancer is the most common neoplasm in women and accounts for 26% (182,460) of all new cancer cases among women. With the use of screening mammography and advancement in other diagnostic modalities, many cases of breast cancer now can be diagnosed and treated at early stages of the disease. Unfortunately, adjuvant chemotherapy regimens commonly used in the treatment of breast cancer may cause premature ovarian failure due to their cytotoxic effects on the germ cells in the ovary. Therefore preservation of fertility in breast cancer survivors at reproductive age has become an important quality of life issue. Fertility preservation is a recently emerged field of reproductive medicine that may help protect the reproductive capability of the cancer survivors and allow them to have children in the future. Embryo freezing is the most established fertility preservation strategy. But conventional ovarian stimulation protocols are contraindicated in breast cancer patients because of the rise of estrogen and its metabolites to supraphysiological levels. Recently developed ovarian stimulation protocols with aromatase inhibitor letrozole and tamoxifen appear to provide a safe stimulation with endogenous estrogen levels comparable with those achieved in the natural cycle. Oocyte freezing can be considered in single women and in those who do not wish donor sperm. Ovarian tissue freezing could also be an option in breast cancer patients who do not wish or have a time for an in vitro fertilization cycle, which requires 10 to 14 days of ovarian stimulation., (Thieme Medical Publishers.)

Although 60 years have passed since the first successful freezing of cells, whole organ freezing is in its initial phase. Heat and mass transfer has limited the success of large tissue and organ cryopreservation either by slow freezing or vitrification. In this article we discuss the limiting factors for the successful freezing of whole organs, such as homogeneous cooling rate, supercooling, latent heat, and recrystallization. We show how the use of directional freezing technology provides solutions to these problems. Whole ovary cryopreservation and transplantation has been proposed as a new method for preserving long-term ovarian function as opposed to ovarian cortical slices. Fertility preservation will benefit from the success of whole ovary freezing and transplantation., (Thieme Medical Publishers.)

Advances in the diagnosis and treatment of childhood, adolescent, and adult cancer have greatly increased the life expectancy of premenopausal women with cancer. The ovaries are very sensitive to cytotoxic treatment, especially to alkylating agents. The only established method of fertility preservation is embryo cryopreservation according to the Ethics Committee of the American Society for Reproductive Medicine (2005), but this option requires the patient to be of pubertal age, have a partner or use donor sperm, and be able to undergo a cycle of ovarian stimulation, which is not possible when the chemotherapy has to be initiated immediately or when stimulation is contraindicated according to the type of cancer. For patients who need immediate chemotherapy, cryopreservation of ovarian tissue is the only possible alternative. This article reports the techniques and results of orthotopic transplantation of cryopreserved ovarian tissue. Among almost 30 cases reported in the literature, 6 live births have been achieved to date., (Thieme Medical Publishers.)

Recently, much progress has been made in the area of cryopreservation of ovarian tissue, one of the only options for fertility preservation available to women who require immediate gonadotoxic chemotherapy. Human ovarian cortical tissue strips have been cryopreserved, thawed, and autotransplanted with successful reproductive function. Cryopreservation of ovarian cortical strips, however, is limited by the ischemia that occurs at the time of retransplantation. Thus for patients that desire long-term resumption of endocrine function, cryopreservation of the whole ovary with an intact pedicle and vascular supply may be a better option. This article describes recent advances in whole ovary cryopreservation in both animal and human models, with a focus on surgical technique for removal, choice of cryoprotectants, freezing and thawing protocols, and preliminary results with organ retransplantation. Although no human cases of whole ovary retransplantation after cryopreservation have been performed to date, these preliminary studies have been encouraging, and it is likely that this option for fertility preservation will be a viable treatment option in the future., (Thieme Medical Publishers.)

Advances in the diagnosis and treatment of childhood, adolescent and adult cancer have greatly increased the life expectancy of premenopausal women with cancer. The ovaries are very sensitive to cytotoxic treatment, especially to alkylating agents. The only established method of fertility preservation is embryo cryopreservation according to the Ethics Committee of the American Society for Reproductive Medicine (2005), but this option requires the patient to be of pubertal age, have a partner or use donor sperm, and be able to undergo a cycle of ovarian stimulation, which is not possible when the chemotherapy has to be initiated immediately or when stimulation is contraindicated according to the type of cancer. For patients who need immediate chemotherapy, cryopreservation of ovarian tissue is the only possible alternative. This manuscript reports the techniques and results of orthotopic transplantation of cryopreserved ovarian tissue. Among almost 30 cases reported in the literature, seven live births have been achieved to date.

Objective: To assess the long-term ovarian function and fertility after heterotopic autotransplantation of frozen-thawed ovarian tissue in cancer patients., Design: Prospective clinical case series., Setting: Academic medical center, Patient(s): Four young cancer patients who completed cancer treatment., Intervention(s): Cryopreserved ovarian tissue (2000-2002) was thawed and transplanted to the heterotopic site (between the rectus muscle and fascia) between 2002 and 2005., Main Outcome Measure(s): [1] Serial blood tests (FSH, LH, estradiol, progesterone, testosterone) and ultrasound examinations. [2] Oocyte retrieval and in vitro fertilization., Result(s): The hormonal profiles were consistent with the postmenopausal level before transplantation. The return of the ovarian function was evidenced by hormonal profiles between 12 and 20 weeks after transplantation. Three patients underwent a second transplantation, as restored ovarian function lasted only 3 to 5 months. After the second transplantation, long-term ovarian function (lasting for 15-41 months) was established in all three patients. Six oocytes (one GV, four MI, one MII) were retrieved from the grafts. Three MI oocytes were developed to full maturity in vitro. Four MII oocytes were fertilized and developed to the cleavage stage embryos (up to six-cell)., Conclusion(s): Autotransplantation of frozen-thawed ovarian tissue to a heterotopic site restored long-term ovarian function (for >40 months), and showed a potential to restore fertility in cancer patients.

During the last decade, new technologies in reproductive medicine have emerged to preserve the fertility of women whose gonadal function is threatened by premature menopause or gonadotoxic treatments. To offer an individualized approach to these patients, different experimental procedures are under investigation, including oocyte cryopreservation and cryopreservation and transplantation of ovarian tissue in the form of cortical fragments, whole ovary or isolated follicles. This review shows that transmission electron microscopy (TEM), combined with other in-vivo and in-vitro analysis techniques, is a valuable tool in the establishment of new experimental protocols to preserve female fertility. Ultrastructural studies allow in-depth evaluation of the oocyte's unique morpho-functional characteristics, which explain its low cryotolerance, and provide essential information on follicular, stromal and endothelial cell integrity, as well as cellular interactions crucial for normal folliculogenesis. In order to be able to offer appropriate and efficient options in every clinical situation, oocyte in-vitro maturation and ovarian tissue transplantation need to be optimized. Further development of new approaches, such as follicular isolation and whole ovary transplantation, should be encouraged. Fine ultrastructural details highlighted by TEM studies will be useful for the further optimization of these emerging technologies.

Background: Successful thawing and orthotopic transplantation of ovarian tissue has produced live offspring in mice, but until now has only been successful for very young ovary donors., Methods: Whole and half ovaries from adult C3H/HeNCrlBR (C3H) and whole ovaries from B6129SF1/J were frozen-thawed and then grafted orthotopically into B6C3F1/CrlBR (B6C3F1) and B6129SF1/J recipients, respectively. In bilateral transplant groups (bilateral), recipients underwent a bilateral ovariectomy, followed by orthotopic grafting. In unilateral groups recipients either underwent bilateral ovariectomy followed by unilateral grafting (unilateral(ovx)) or had only one ovary removed and replaced with a graft (unilateral) along with complete transection of the remaining oviduct., Results: Ovary size and number of follicles decreased dramatically in grafted compared with control groups, but the loss in the unilateral(ovx) group was significantly less than in the unilateral group. Similar numbers of litters and litter size were obtained in bilateral and unilateral grafts of fresh ovary. However, a much lower number of litters and litter size were derived from unilateral grafts than from unilateral(ovx) grafts of frozen ovary., Conclusions: Normal fertility can be restored by orthotopic grafting of fresh or frozen adult mouse ovaries and no significant difference between fresh and frozen ovaries was found. Grafting of half ovaries does not alter the overall fertility rate. Unilateral(ovx) grafting is an efficient procedure to produce live pups and removes the negative effect of recipient native ovaries on post-grafting fertility.

Objective: The objective was to assess the natural pregnancy of rabbits subjected to bilateral oophorectomy and orthotopic allogeneic intact and sliced ovarian transplantation without a vascular pedicle, and to determine the morphofunctional aspects of the transplanted ovaries., Study Design: Thirty-two female rabbits were studied. The ovaries were removed and orthotopically transplanted without vascular anastomoses between the two breeds of rabbits. In Group 1 (n=8), only laparotomy and laparorrhaphy were performed, in Group 2A (n=8) intact ovaries were transplanted on both sides, in Group 2B (n=8) both ovaries were sliced and orthotopically transplanted, and in Group 2C (n=8) an intact ovary was transplanted on one side and a sliced ovary on the other side. Three months later, the animals were paired with males for copulation. Estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone levels were assessed. A histologic study was carried out and the numbers of pregnancies and litters were also determined., Results: Pregnancies occurred in seven rabbits in Group 1, 37.5% of rabbits in Group 2A, 50% in Group 2B, and 62.5% in Group 2C. Hormone levels and histology confirmed the vitality and function of all ovaries., Conclusions: Intact or sliced orthotopic allogeneic ovarian transplantation without a vascular pedicle is viable in rabbits, and preserves their hormonal and fertile functions.

Background: Aggressive chemotherapy/radiotherapy for cancer may cause gonadal failure in young female survivors. The putative aim of ovarian tissue cryopreservation is to restore fertility by transplantation of a patient's frozen-thawed ovarian tissue or, further into the future, by in vitro maturation of frozen-thawed oocytes followed by in vitro fertilization. This report presents our early experience with ovarian tissue preservation in young patients., Methods: We conducted a database review of the techniques and outcomes of the ethics board-approved ovarian tissue cryopreservation procedures performed at our center since 1998 for young girls with malignancy., Results: The study group included 23 patients (median age = 14 years) with various types of cancer (hematologic, bone, ovarian, or intracranial); 11 patients were scheduled for chemotherapy, 11 patients had already undergone some form of chemotherapy before the ovarian tissue harvesting, and 1 patient was not scheduled for chemotherapy. Ten underwent bone marrow transplantation after tissue retrieval. Twenty-one patients underwent laparoscopic harvesting of their ovarian tissue. In the other 2 patients, the ovary was preserved during inguinal hernia repair or tissue was obtained at laparotomy for a pelvic tumor. All patients had benign operative and postoperative courses., Conclusions: Laparoscopy for ovarian tissue retrieval for cryopreservation is safe in young cancer patients. Based on reports of successful cryopreservation of human ovarian tissue containing primordial follicles, we believe that this approach holds promise for female cancer survivors.

Background: Unfertilized oocytes, embryos and ovarian issue can be cryopreserved before cancer treatment of post-pubertal women. Fertility may be restored by retransplantation in women who are pronounced healthy., Material and Methods: The article is based on relevant literature and our own clinical experience since 2004, when the procedure was first allowed in Norway., Results and Interpretation: Cryopreservation of ovarian tissue is an established procedure in Norway. As of January 2007, ovarian tissue from 22 women, aged 14-35 years, has been cryopreserved at Rikshospitalet. There is an upper age limit of 35 years because of age-related follicular loss. The treating oncologist and a gynaecologist should be responsible for informing patients about the possibility of preserving fertility by ovarian cryopreservation before chemo- and/or radiation therapy. The patient should, at the same time, be told about the limited world-wide experience with this procedure.

Unlabelled: Cancer is not rare in younger women. There has been a remarkable improvement in the survival rates due to progress in cancer treatment. The necessary treatment for most of the common cancer types occurring in younger women implies either removal of the reproductive organs or cytotoxic treatment that could partially or definitively affect reproductive function. Early loss of ovarian function not only puts the patients at risk for menopause-related complications at a very young age, but is also associated with loss of fertility. Further, women in the western hemisphere have been delaying initiation of childbearing to later in life. The results of these changes have led to an increase in patients facing the risk of premature ovarian failure, and therefore seeking help in preserving their fertility. This increase in demand has resulted in a proliferation of techniques to preserve fertility. Indeed, the number of options is increasing; some are more established procedures, such as embryo cryopreservation, and some are still experimental, such as ovarian cryopreservation. Because of the variations in type and dose of chemotherapy, the type of cancer, the time available before onset of treatment, the patient's age and the partner status, each case is unique and requires a different strategy of fertility preservation., Target Audience: Obstetricians & Gynecologists, Family Physicians., Learning Objectives: After completion of this article, the reader should be able to recall the potential early loss of ovarian function secondary to radiotherapy and/or chemotherapy for cancer at a young age; explain the increasing demands for fertility preservation; and summarize the limited number of proven, safe, and efficacious methods.

Although currently investigational, ovarian tissue cryopreservation and oocyte cryopreservation hold promise for future female fertility preservation, particularly following aggressive chemotherapy and/or radiotherapy treatment protocols.

Objective: To assess the natural pregnancy and to determine the morphofunctional aspects of ovaries of rabbits submitted to bilateral oophorectomy and orthotopic allogeneic or autologous intact and sliced ovarian transplantation without a vascular pedicle., Methods: Fifty-six female New Zealand White and California rabbits were studied. The ovaries were removed and orthotopically transplanted or replaced without vascular anastomoses: Group 1 (n = 8), only laparotomy and laparorrhaphy were performed; Group 2A (n = 8) intact ovaries were reimplanted on both sides; Group 2B (n = 8) both ovaries were sliced and orthotopically reimplanted; Group 2C (n = 8), an intact ovary was reimplanted on one side and a sliced ovary on the other side; Group 3A (n = 8) intact ovaries were transplanted on both sides, Group 3B (n = 8) both ovaries were sliced and orthotopically transplanted, Group 3C (n = 8), an intact ovary was transplanted on one side and a sliced ovary on the other side. Three months later, the females were paired with males for copulation. Estradiol, progesterone, follicle stimulating hormone and luteinizing hormone levels were assessed. The morphological aspect of the ovaries was studied and the number of pregnancies and litters were also determined. The number of successful pregnancies and the number of litters was compared between the groups by the chi-square test. One-way ANOVA and the Tukey-Kramer tests compared the hormonal dosages. The significance was of p < 0.05., Results: Pregnancies occurred in seven (87.5%) rabbits of Group 1, in 37.5% in Groups 2A and 3A, in 50% of groups 2B, 2C and 3B, and in 62.5% of group 3C. Hormone levels and histology confirmed the vitality of all ovaries., Conclusion: Intact or sliced orthotopic allogeneic and autologous ovarian transplantation without a vascular pedicle is viable in rabbits, and preserves their fertility and hormonal functions.