Cervical Infection as a Novel Risk Factor for Perineal Obstetrical Trauma: A Cross-Sectional Study

Background/Objectives: Perineal obstetrical trauma sustained during vaginal delivery has a profound impact on female quality of life. The aim of the cross-sectional study was to analyze the association between active bacterial cervical infection and group B Streptococcus (GBS) rectovaginal colonization in the 35th-37th weeks of pregnancy with the degree of delivery perineal trauma. Methods: The study included 778 women after vaginal delivery. Maternal characteristics, including age, concomitant diseases, parity, obstetrical history, and cervical swab results conducted at admission and rectovaginal bacterial swabs at the 35th-37th weeks of pregnancy, were analyzed. The rates of perineal tears were compared between the physiological and pathological cervical swab groups and between the GBS-positive and GBS-negative colonization groups. Results: At admission to delivery, active cervical infection was diagnosed in 269 (35.9%) women. After vaginal delivery, 361 (49.3%) women had an intact perineum, and 288 (39.3%), 78 (10.7%), 4 (0.6%), and 1 (0.1%) had 1st-4th-degree perineal tears, respectively. Statistical analyses of the logistic regression model found that GBS colonization at the 35th-37th weeks of pregnancy (OR 1.56, p = 0.035) and pathological flora at admission (OR 1.54, p = 0.019) were associated with perineal tears. A higher vaginal parity was found to be a protective factor (OR 0.49, p < 0.000). Conclusions: High birthweight, longer second stage of labor duration, and primiparity were associated with increased rates of perineal trauma. Active cervical infection at admission and GBS colonization at the 35th-37th weeks of pregnancy were found to be risk factors for perineal tears. A protective factor for an intact perineum was a higher number of prior vaginal deliveries.