Findings of Mild Adenomyosis on Transvaginal Ultrasound Do Not Impact Pregnancy Rate or Pregnancy Outcomes in Single Euploid Frozen Embryo Transfers

The effect of adenomyosis on infertility treatment outcomes has been evaluated with mixed results. This question is further complicated by heterogeneity in the diagnosis and classification of adenomyosis. In 2019, the Morphological Uterus Sonographic Assessment (MUSA) group published a uniform classification and reporting system for description of adenomyosis, allowing for greater standardization. We sought to evaluate whether the presence of mild adenomyosis impacts the outcomes of single euploid frozen embryo transfers from conception to birth.

We performed a retrospective analysis of single euploid embryo transfers at a single academic center from March 2018 to March 2023. Baseline characteristics and pregnancy outcomes when available were obtained from the electronic medical record. Two- and three-dimensional ultrasound images were assessed for mild adenomyosis by two reviewers using MUSA criteria. Statistical analyses were conducted utilizing chi-squared and Kruskal-Wallis tests with significance indicated by P < 0.05.

A total 282 frozen embryo transfer (FET) cycles of a single euploid embryo were performed during the study period. Of these cycles, 31 (11.0%) had ultrasound findings consistent with mild adenomyosis. Baseline characteristics between patients with and without ultrasound findings of adenomyosis, including age at oocyte retrieval, age at embryo transfer, BMI, history of cesarean section, and history of uterine surgery, were not significantly different. Pregnancy outcomes did not differ between the two groups. Implantation rate was 70% in those without adenomyosis vs. 81% in those with adenomyosis (P = 0.22). Clinical pregnancy rate was 89% in those without adenomyosis vs. 88% in those with adenomyosis (P = 0.85). Miscarriage rate was 16% in those without adenomyosis vs. 9% in those with adenomyosis (P = 0.38). Live birth rate was 80% in those without adenomyosis vs. 91% in those with adenomyosis (P = 0.24).

The presence of mild adenomyosis findings on ultrasound did not negatively impact implantation, clinical pregnancy, miscarriage, or live birth rates. It also did not negatively impact pregnancy outcomes.