Independent association between uterine malformations and cervical insufficiency: a retrospective population-based cohort study.

Objective: The purpose of our study was to explore maternal and fetal outcomes in the second and third trimester in women with uterine malformations.
Study Design: This was a retrospective population-based cohort study including women with a diagnosis of uterine malformation arised from workup for infertility or recurrent pregnancy loss, was accidental during pregnancy, or was noticed at the time of cesarean delivery.
Results: A total of 280,721 pregnancies met the inclusion criteria and were divided into two study groups: (1) pregnancies in women with uterine malformations (n = 1099); and (2) controls (n = 279,662). The rate of women presenting uterine malformations was 0.39%. The prevalence of cervical os insufficiency was significantly higher in women with a uterine malformation than in the control group (3.6 vs. 0.4%, p < 0.001). A multivariate analysis, performed to evaluate risk factors for cervical insufficiency in women with uterine malformations. Mullerian anomalies (OR 6.19, 95% CI 4.41-8.70, p < 0.001), maternal age (OR 1.05, 95% CI 1.04-1.06, p < 0.001), recurrent abortions (OR 12.93, 95% CI 11.43-14.62, p < 0.001), and ethnicity (OR 2.86, 95% CI 2.454-3.34, p < 0.001) were found to be independently associated with the development of cervical insufficiency.
Conclusion: Uterine anomalies have a strong association with cervical insufficiency. Women with uterine anomalies have an increased risk to develop pregnancy complications that arise from a loss in cervical function during the midtrimester or early third trimester.