The impact of uterine fibroids on obstetric complications and pregnancy outcomes in twin pregnancies: A single-center cohort study

Background: Uterine fibroids are the most common benign tumors in the female reproductive system and can affect fertility, conception, and implantation. Despite their prevalence, few studies have examined fibroids impact on twin pregnancies. This study investigates the effects of uterine fibroids on obstetric complications and pregnancy outcomes in twin pregnancies. Methods: We conducted a retrospective cohort study of patients who delivered twins at West China Second University Hospital of Sichuan University from October 1, 2019 to October 1, 2024. The study population was divided into three groups: (1) the fibroid group, including twin pregnancies with uterine fibroids; (2) the non-fibroid group, including twin pregnancies without uterine fibroids; and (3) the myomectomy group, including twin pregnancies with a history of myomectomy. Data collected and compared included maternal age, body mass index at delivery, parity, previous preterm birth, gestational age, mode of conception, hospitalization cost, fibroid size and number, obstetric complications and pregnancy outcomes. Results: A total of 4,766 twin pregnancies were included in this study. Statistical analyses revealed no significant differences in obstetric complications and pregnancy outcomes between the three groups, except for delivery before 37 weeks ( p = 0.020). Notably, the prevalence of gestational diabetes mellitus was higher in women with larger fibroids (41.79%) compared to those with smaller fibroids (28.42%, p = 0.033) and those without fibroids (26.44%, p = 0.005). Additionally, there was a higher prevalence of placenta previa in women with larger fibroids (10.45%) compared to those with smaller fibroids (3.08%, p = 0.016) and those without fibroids (3.75%, p = 0.014). Conclusion: This study found that twin pregnancies complicated by large uterine fibroids were associated with a higher prevalence of gestational diabetes mellitus and placenta previa.