L26/P-323 Impact of Endometriosis on cumulative live birth rates after donor sperm intrauterine insemination

Abstract Study question Does endometriosis impact the live birth rate after donor sperm intra uterine insemination (IUI)? Summary answer Women with endometriosis have a lower cumulative live birth rate after donor sperm IUI compared to those without the condition. What is known already Endometriosis is a frequent cause of infertility, often impairing spontaneous conception through inflammatory, anatomical, and endocrine mechanisms. While IUI may be proposed in infertile women with minimal to mild endometriosis with patent tubes, In vitro fertilization is usually favored due to its ability to bypass potential tubal damage and the adverse peritoneal environment, including inflammatory and immune-mediated factors. In women presumed to be fertile undergoing donor sperm, the effectiveness of IUI as first-line approach in the presence of endometriosis remains poorly documented, and no specific recommendations are currently available. Study design, size, duration This was a retrospective observational cohort study conducted at a university-based reproductive medicine center. We included all women who underwent IUI with donor sperm between November 1st, 2021, and September 1st, 2024. Participants/materials, setting, methods Participants were divided into two groups: the “exposed” group (women with endometriosis) and the “unexposed” group (women without endometriosis). Endometriosis diagnosis was based on published imaging criteria (transvaginal ultrasound and/or magnetic resonance imaging) and with histological confirmation in women who had undergone previous surgery. The primary outcome was the cumulative live birth rate (cLBR) per patient, defined as the proportion of women who achieved at least one live birth across all their IUI attempts. Main results and the role of chance A total of 541 women (1497 IUI cycles) was included: 94 with endometriosis and 447 without. The mean age was 36.9 ± 3.9 years in the endometriosis group and 36.6 ± 4.1 years in controls (p = 0.520). The average number of IUI cycles per patient was similar (2.7 ± 1.4 vs. 2.9 ± 1.8, p = 0.615). Among the women with endometriosis, phenotypic distribution was as follows: isolated superficial peritoneal endometriosis in 7 patients (7.4%), ovarian endometriosis (OMA) without associated DIE in 7 patients (7.4%), and deep infiltrating endometriosis (DIE) in 80 patients (85.1%). cLBR was 20.2% (19/94) in women with endometriosis and 32.2% (144/447) in control group (p= 0.021). After multivariate analysis, endometriosis was independently associated with a reduced cumulative live birth rate following IUI with donor sperm (OR = 0.5; 95% CI: 0.3–0.9). Limitations, reasons for caution The main limitation is the single-center retrospective design. Wider implications of the findings Despite lower success rates, donor sperm IUI remains a valid first-line strategy for women with endometriosis who are not infertile. Prospective, randomized studies are needed to confirm the role of IUI in this population. Trial registration number No