P-379 Fertility outcomes several years after fertility preservation for endometriosis

To study the fertility outcomes of women who tried to conceive at least 2 years after fertility preservation (FP) for endometriosis.

To advise patients with endometriosis on the benefit of FP, particulary on the utilization rates of frozen oocytes and the actual chances of pregnancy

Endometriosis is found in 25-40% of infertile patients. Due to the multiple and recurrent nature of lesions and the significant incidence of repeated ovarian surgery, endometriosis increase the risk of damaging the ovarian follicular stockpile. Since the revision of the French bioethics law (2014), women with endometriosis can be offered FP techniques. However, there is currently little data available in this population, limiting the possibility to establish formal recommendations

A retrospective observational, bicentric cohort study conducted at Antoine Beclère and Jean Verdier University Hospitals.Inclusion criteria were: i) patients with confirmed endometriosis using imaging (pelvic MRI or ultrasound scan); ii) controlled ovarian hyperstimulation for FP between from July 1st 2013, and December 31st, 2019 (n = 200). The endpoint date was February 15, 2023, with data collected retrospectively.

Cumulative incidences of pregnancy and live birth were calculated. Time to conception, time to utilization of oocytes, and predictive factors for pregnancy and live birth were assessed using logistic regression Cox models.

Among the 184 patients with available data after FP for endometriosis, 76 attempted to conceive (41%). The mean number of oocytes vitrified per patient were 14.7 ± 7.6 [8-20]. Patients attempting conception at least 2 years post-FP were more likely to have a partner at the first consultation (70.7% vs. 25.7%, p < 0.0001). Overall, 48 patients (43%) achieved a pregnancy, predominantly through spontaneous conception (50%), frozen-thawed oocytes (37.5%), or a new IVF attempt using fresh eggs (12.5%). Among those attempting conception, 31 (39%) reported a live birth. Cumulative chances of pregnancy at 4 years post-FP were estimated at 52% CI 95% [41% - 65%]. Utilization rates for frozen oocyteswere 7% CI 95% [4% - 12%] and 18% CI 95% [13% - 26%], respectively, 2 and 5 years post-freezing. Nulliparity was the only factor significantly associated with an increased probability of oocyte utilization (RR = 1.43 [1.0 - 2.06]).

The result should be interpreted with caution due to the small sample size of our study. Data were collected retrospectively and some information, concerning obstetrical and neonatal information where missing. Furthermore, the duration of the follow up time was too short to evaluate long-term fertility.

Despite endometriosis affecting fertility, our study revealed that half of pregnancies occurred spontaneously, irrespective of the endometriosis phenotype. These findings provide valuable insights into advising women on the utilization rates of frozen oocytes (7% to 18%) and the relatively high chances of natural conception after FP for endometriosis.

NA