P-318 The cumulative live birth rate in women undergoing IVF is not impacted by an endometriosis diagnosis

Abstract Study question Does endometriosis affect the cumulative live birth rate in patients undergoing IVF compared to matched controls? Summary answer The cumulative live birth rates of patients with endometriosis are comparable to those of matched patients with other infertility factors undergoing IVF. What is known already Endometriosis-related infertility is a condition whose underlying pathogenic mechanisms remain incompletely understood. The impact of endometriosis on IVF outcomes represents a subject of ongoing debate. While some meta-analyses have reported poorer IVF outcomes in patients with endometriosis, other studies have shown comparable success rates. A previous analysis conducted in our unit highlighted that endometriosis negatively affects IVF outcomes, but only regarding quantitative aspects on folliculogenesis, not qualitative ones. Given that endometriosis is a chronic condition, our aim was to assess its potential impact on IVF success rates across multiple attempts and over time. Study design, size, duration This is an observational case-control study that included 496 patients who underwent their first IVF cycle between January 2014 and December 2020 at the Infertility Unit of the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico of Milan, Italy. The last follow-up of the patients was conducted in December 2024. Participants/materials, setting, methods A total of 248 patients with endometriosis were selected and matched with 248 patients without the disease. The inclusion criteria were as follows: age at the first cycle under 43 years old, AMH>1.1 ng/ml and no prior IVF cycles. Endometriosis patients (cases) were matched with women without endometriosis (controls) considering age, study period and serum AMH concentration at the time of the first attempt. Main results and the role of chance Among baseline clinical characteristics, only body mass index (20.8 [19.5 – 22.6] vs 22.1 [20.0 – 24.8], p < 0.001) and duration of infertility (2 years [1.5 – 3] vs 3 [2 – 4], p < 0.001) showed significant differences between cases and controls. Regarding the first IVF cycle, the total dose of gonadotropin used was significantly higher in patients with endometriosis (1900 [1500 – 2475] vs 1800 [1350 – 2250], p = 0.02), but the number of oocytes retrieved was significantly lower (6 [4 – 11] vs 8 [4 – 12], p = 0.02). Live birth rates for the first (44 vs 37%, p = 0.12) and the second IVF cycle (39 vs 29%, p = 0.11) did not differ significantly between women with and without endometriosis, respectively. The cumulative live birth rate was similar among the two groups (64% vs 57%, p = 0.14) while the time to pregnancy was significantly lower in patients with endometriosis (3 months [0–10] vs 5 [2–12], p = 0.02). The Kaplan-Meyer curve based on time to pregnancy showed a marginally significant difference (p = 0.049), in favor of endometriosis. The dropout rate after the first IVF cycle did not differ significantly between the two groups (29 vs 22%, p = 0.21). The same applies to the second attempt (33 vs 36%, p = 0.72). Limitations, reasons for caution This is a retrospective study that includes only patients with good ovarian reserve, and may not always represent the profile of endometriosis patients in IVF centers. Wider implications of the findings Endometriosis is not related to a lower live birth rate after ART treatments compared to other causes of infertility. IVF represents an effective option for overcoming endometriosis-related infertility. Trial registration number No