Efficacy of ovarian tissue cryopreservation for fertility preservation: lessons learned from 545 cases

Study question How effective is ovarian tissue cryopreservation (OTC)? Summary answer In our cohort of patients who underwent OTC, premature ovarian failure (POF) rates, return rates and pregnancy rates after autotransplantation were 31.5, 4.4 and 33%, respectively. What is known already OTC for fertility purposes has been performed for >20 years now. With over 86 live births reported worldwide and success rates of ~30% after autotransplantation of frozen-thawed ovarian cortex, the procedure should no longer be considered experimental. However, very few publications report the efficacy of this procedure. Study design, size, duration Cases of ovarian tissue cryobanking for fertility preservation performed between 1997 and 2013 in a single institution were reviewed by analysis of the cryobank database and a prospective questionnaire sent out in March 2015. Participants/materials, setting, methods There were 545 patients who underwent OTC during this period. The analysis included indications for OTC, survival rates, ovarian function and spontaneous pregnancies after OTC, come-back rates for ovarian tissue transplantation, pregnancy rates after transplantation, and complication and satisfaction rates. Main results and the role of chance OTC was performed in this cohort at a mean age of 22.3 ± 8.8 years for oncological indications (79%), benign gynecological pathologies (17.5%) and genetic risks of POF (3.5%). Of the 545 patients, 29% were under 18 years of age at the time of OTC and 15% were prepubertal. While 10% of patients died from their disease, 21 patients (3.9%) underwent autotransplantation, 7 of whom delivered a healthy baby, yielding a post-transplantation live birth rate of 33%. Of 451 patients who were sent the questionnaire, 143 agreed to respond (32%). Nevertheless, ovarian function could not be evaluated in 36% of those who answered. Of 92 evaluable patients, 31.5% were menopausal and 68.5% showed persistent ovarian function. Of 52 women who attempted to conceive naturally, 37 were successful (71%). Among 140 patients who answered the questionnaire, 96% were satisfied with the procedure and only 1 major complication (intra-abdominal hemorrhage) was encountered. Among all the patients, 12% have donated their ovarian cortex for research purposes or have had it destroyed. Limitations, reasons for caution The questionnaire participation rate (32%), limited follow-up (mean 7.6 ± 3.5 years) and use of only clinical criteria for evaluation of ovarian function made it difficult to accurately assess the risk of POF and efficiency of OTC. Wider implications of the findings Our findings confirm a 30% pregnancy rate after ovarian cortex autotransplantation but also stress the difficulties of evaluating the real efficacy of OTC. Study funding/competing interest(s) No funding was sought for this study and none of the authors have any conflict of interest. Trial registration number ClinicalTrials.gov Registration ID: CRYOFONOV01.