Uterine fibroids detected in early pregnancy and their association with adverse pregnancy outcomes: a single-centre retrospective cohort study

This study aimed to evaluate the association between uterine fibroids detected in early pregnancy and subsequent adverse pregnancy outcomes in women. A retrospective analysis was conducted on 39,244 deliveries at Hangzhou Women’s Hospital from January 2018 to December 2020. Women were grouped into those with uterine fibroids detected in early pregnancy (n = 674) and those without (n = 38,570). Fibroids were diagnosed by ultrasound at 4–8 weeks using Morphological Uterus Sonographic Assessment (MUSA) criteria. Multivariable binary logistic regression was conducted to assess the association between uterine fibroids and adverse pregnancy outcomes, adjusting for maternal age, BMI, parity, hyperlipidemia, obesity, and other clinically relevant confounders. The model also accounted for thyroid function and uterine scar history, while mode of delivery was treated as an outcome variable. After adjusting for confounders, uterine fibroids were significantly associated with cesarean delivery [aOR = 1.285 (1.089–1.517)], post-term pregnancy [aOR = 1.866 (1.088–3.203)], and late-pregnancy anemia [aOR = 1.244 (1.048–1.476)]. Obesity (BMI ≥ 30 kg/m²) and hyperlipidemia were more prevalent in women with fibroids but were treated as confounders in adjusted models. Multiparity was protective against fibroid detection [aOR = 0.540 (0.450–0.647)]. An inverse association was observed between fibroids and gestational hypothyroidism [aOR = 0.277 (0.170–0.449)]. Women with uterine fibroids detected in early pregnancy were significantly more likely to undergo cesarean delivery, experience post-term pregnancy, and develop anemia in late pregnancy. Advanced maternal age and fewer prior births increased fibroid detection rates, while fibroids appeared protective against hypothyroidism during pregnancy.