<p>This study aimed to investigate the association between sonographic features of adenomyosis defined by the revised MUSA criteria and pregnancy outcomes in women undergoing in vitro fertilization (IVF) and embryo transfer (ET). All autologous ET cycles at a university-affiliated infertility center in Seoul, South Korea, between May 2022 and January 2024 were included in this study. All patients undergoing IVF were examined by the ultrasound strictly adhering to the revised MUSA definition at the time of examination. Patients with sonographic features of adenomyosis were assigned to the adenomyosis group (<i>n</i> = 300). During the same period, an age-matched 1:1 control group (<i>n</i> = 300) was selected from women who underwent embryo transfer and had no sonographic features of adenomyosis. Logistic regression analysis and generalized estimating equations were used to evaluate which specific sonographic features of adenomyosis are associated with pregnancy outcomes. Among the MUSA features, the interrupted junctional zone was the only independent factor significantly associated with a lower chance of clinical pregnancy (aRR = 0.75, 95% CI 0.58–0.95, <i>p</i> = 0.020), ongoing pregnancy (aRR = 0.72, 95% CI 0.52–0.99, <i>p</i> = 0.049), and an increased risk of biochemical pregnancy loss (aRR = 1.98, 95% CI 1.02–3.84, <i>p</i> = 0.044). This finding suggests that sonographic evaluation of the junctional zone should be considered in women with adenomyosis who desire pregnancy.</p>