Impact of junctional zone adenomyosis on reproductive outcomes after first single embryo transfer with donated oocytes: A retrospective single‐center cohort study

OBJECTIVE: To evaluate whether junctional zone (JZ) adenomyosis adversely affects assisted reproductive technologies (ART) outcomes in infertile women undergoing their first single embryo transfer (SET) using donor oocytes. METHODS: This retrospective single-center cohort study was conducted at Instituto Bernabeu (Alicante, Spain). A total of 240 infertile women undergoing their first SET with donor oocytes between December 2021 and June 2024 were included: 120 with isolated JZ adenomyosis diagnosed by two-dimensional (2D)-three-dimensional (3D) transvaginal ultrasound according to morphological uterus sonographic assessment (MUSA) criteria, matched to 120 controls without uterine abnormalities. Primary outcomes were live birth and miscarriage rates. Secondary outcomes included implantation rate and the relationship between adenomyosis severity and reproductive outcomes. Multivariable models were used to adjust for potential confounders. RESULTS: Women with JZ adenomyosis had significantly lower live birth rates than controls (34.16% vs 50.83%; P = 0.009) and higher miscarriage rates (32.93% vs 11.11%; P < 0.001), while implantation rates were comparable (68.33% vs 75.00%; P = 0.25). JZ adenomyosis independently predicted reduced live birth (odds ratio [OR] 0.43, 95% confidence interval [CI]: 0.24-0.76; P = 0.004) and increased miscarriage risk (OR 3.33, 95% CI: 1.42-7.82; P = 0.005). Increasing disease severity was associated with a higher risk of miscarriage. CONCLUSION: JZ adenomyosis is associated with significantly lower live birth rates and higher miscarriage rates after a first SET with donor oocytes, despite similar implantation rates. Comprehensive pre-ART ultrasound assessment of the JZ may improve counseling and support targeted strategies to optimize reproductive outcomes.