Adenomyosis, especially in its focal nature, hampers implantation and live birth rate after single euploid embryo transfer.

Objective: The primary objective of this study was to assess if uterine adenomyosis impacts live birth rate per euploid embryo transfer. The secondary objectives included addressing obstetric and perinatal outcomes in the study group.

Methods: This was a multicenter and retrospective cohort study in which 228 patients diagnosed with adenomyosis undergoing single euploid embryo transfer between 2016 and June 2023 were included and matched on 1:1 ratio to control patients without ultrasonographic diagnostic criteria for adenomyosis.

Results: A significant higher live birth rate per embryo transfer was observed in controls compared to women with adenomyosis: 107/228 (46.9%) versus 56/228 (24.6%), respectively (odds ratio (OR) = 2.71, 95% confidence interval [CI]: 1.73-4.13, p < 0.001). When dividing adenomyotic patients regarding the nature of the disease, a higher live birth rate per transfer was described in diffuse adenomyosis compared to focal adenomyosis: 47/166 (28.3%) versus 9/62 (15%), respectively (OR = 2.32, 95% CI: 1.03-5.78, p = 0.034). Described differences were constant even when correcting for multiple variables. There was no statistically significant difference in childbirth delivery method (vaginal vs. cesarean section) between the adenomyosis and control groups. Mean gestational age at the time of delivery, newborn size and weight, and incidences of low birth weight, preterm birth, and admission to the neonatal intensive care unit did not differ between the two groups. In addition, in vitro fertilization (IVF) and perinatal outcomes were similar in patients with diffuse compared with focal adenomyosis.

Conclusion: Adenomyosis, especially focal adenomyosis, affects clinical but may not affect perinatal outcomes after single euploid embryo transfer.