Relationship between unremoved cervical polyp in pregnancy and spontaneous preterm birth

BACKGROUND: Cervical polyps removed during pregnancy have been reported to be associated with preterm birth; however, the association between unremoved cervical polyps and preterm birth has not been elucidated. OBJECTIVE: This study aimed to clarify the relationship between cervical polyps detected before 12 weeks of gestation managed expectantly and spontaneous preterm birth. STUDY DESIGN: This retrospective cohort study included pregnant women who visited a tertiary perinatal center before 12 weeks of gestation between January 2015 and December 2019. The exclusion criteria were as follows: multiple gestations, loss or termination of pregnancy before 12 weeks of gestation, major fetal anomalies, fetal chromosomal abnormalities, fetal demise, having undergone removal of cervical polyps before the first visit to our hospital, and moving to other hospitals before delivery. A vaginal speculum examination was routinely performed during a prenatal visit before 12 weeks of gestation. When a cervical polyp was detected on speculum examination, it was managed expectantly, unless gynecologic malignancy was suspected. Relationships between cervical polyps and spontaneous preterm birth before 34 weeks of gestation were evaluated using logistic regression analysis and Cox proportional-hazards analysis adjusted for known confounders for spontaneous preterm birth. RESULTS: A total of 4172 pregnant women were included, of whom 92 (2.2%) had a cervical polyp detected before 12 weeks of gestation. None of the women underwent polypectomy during pregnancy. The incidence of spontaneous preterm birth before 34 weeks of gestation was higher in pregnant women with cervical polyps than in those without them (5.4% vs 0.7%; P<.01). Logistic regression analysis revealed that cervical polyps were an independent risk factor for spontaneous preterm birth before 34 weeks of gestation (adjusted odds ratio, 4.09; 95% confidence interval, 1.70-9.81; P<.01). The adjusted hazard ratio for spontaneous preterm birth before 34 weeks of gestation among women with vs without cervical polyps was 2.95 (95% confidence interval, 1.32-6.62; P<.01). CONCLUSION: Cervical polyps detected before 12 weeks of gestation managed expectantly are a significant risk factor for spontaneous preterm birth before 34 weeks of gestation.