Pregnancy outcomes following ovarian tissue cryopreservation: an Australian cohort study

Abstract

Background: Ovarian tissue cryopreservation is an increasingly utilized fertility preservation method in young women, with this technique being largely implemented across Europe and Australia. Australia is a pioneer of ovarian tissue cryopreservation, but the clinical perinatal outcomes are currently unknown for the Australian population. These outcomes are important as they contribute to the global understanding of which patients can benefit from this fertility preservation option.

Objective: To examine the pregnancy and mortality outcomes of patients who have undergone ovarian tissue cryopreservation and/or ovarian tissue transplantation in Victoria, Australia, and investigate predictors of success.

Study design: A retrospective cohort study was conducted including patients who underwent ovarian tissue cryopreservation from July 1995-July 2022 at the largest ovarian tissue cryopreservation center in Victoria, Australia. Patients over the age of 18 at the time of the study were included in the study. Perinatal and mortality data were obtained through data linkage from the Victorian Perinatal Data Collection and Births Deaths and Marriages databases.

Results: Overall, 593 patients had undergone ovarian tissue cryopreservation between July 1995 and July 2022 in Victoria, Australia. All 593 patients were successfully linked to the perinatal and mortality databases, of whom 6 (1.0%) had pregnancies lacking perinatal data, and 17 had mortality data not reflected in the linkage but next of kin reported their deaths to the ovarian tissue cryopreservation providing clinic. Of this cohort, 48 (8.1%) underwent ovarian tissue transplantation and 106 (17.9%) died from complications of their medical indication for tissue freezing. A total of 192 neonates from 114 women were reported from both transplant (n=12/48, 25.0%) and nontransplant (n=102/545, 18.7%) cohorts. Most women had reported pregnancies by 15 years after ovarian tissue cryopreservation, with transplant cases having a similar overall pregnancy rate as per the time-to-event analysis (adjusted subdistribution hazard ratio 1.378, 95% confidence interval 0.755-2.515, P=.296).

Conclusion: This is a large single-center cohort study within the southern hemisphere that investigates patients who have undergone ovarian tissue cryopreservation, with one in 5 women achieving a pregnancy, emphasizing the clinical feasibility of ovarian tissue cryopreservation as a fertility preservation option for future fertility counseling.

Keywords: fertility preservation; live birth; ovarian tissue cryopreservation; ovarian tissue transplantation; perinatal outcomes; pregnancy.