Not all adenomyosis is equal: impact of direct adenomyosis features on live birth after ART cycles in a prospective cohort study

Objective To evaluate whether the presence and type of ultrasound markers of adenomyosis, as defined by MUSA criteria, predict IVF/ICSI outcomes, specifically live birth and pregnancy loss rates. Methods This single-center prospective cohort study included 314 women aged 18–39 years undergoing their first IVF/ICSI cycle between March 2018 and March 2020. All participants underwent standardized transvaginal ultrasound before treatment. Adenomyosis was diagnosed using MUSA criteria, distinguishing direct markers (myometrial cysts, hyperechogenic islands, echogenic subendometrial lines; n = 54) from indirect markers (globular enlargement, asymmetrical thickening, junctional zone irregularity; n = 22). Two multivariate logistic regression models were performed: (i) all adenomyosis patients versus controls ( n = 238), and (ii) direct marker patients versus controls, adjusting for maternal age, BMI, and embryo transfer stage. Results Among the adenomyosis group, 71.1% exhibited direct markers. Overall, adenomyosis was associated with reduced live birth per embryo transfer (28.9% vs 40.3%, aOR 0.61, 95% CI 0.34-1.08, p = 0.094) and significantly increased total pregnancy loss among HCG-positive patients (41.0% vs 22.6%, aOR 2.49, 95% CI 1.11-5.59, p = 0.026). When restricting analysis to direct markers, associations became substantially stronger: live birth rate was 22.2% (aOR 0.42, 95% CI 0.20-0.84, p = 0.017), representing a 58% reduction in odds, and pregnancy loss rate was 48.0% (aOR 3.77, 95% CI 1.44-10.21, p = 0.007), conferring a nearly 4-fold increased risk. Blastocyst-stage transfer independently improved live birth rates but did not compensate for the negative effect of direct markers. Conclusion Direct ultrasound markers of adenomyosis identify a high-risk reproductive phenotype with substantially reduced live birth and markedly elevated total pregnancy loss risk in IVF/ICSI cycles. The presence and type of ultrasound markers, rather than adenomyosis as a binary diagnosis, should inform patient counseling and individualized treatment planning.