Objective: Our objectives were to study the association between epidural analgesia and risk of severe perineal tears (SPT), and identify additional risk factors for SPT.
Methods: We conducted a historical cohort study of women with term delivery between 2006 and 2011. Inclusion criteria were an uncomplicated singleton pregnancy, cephalic presentation and vaginal delivery. Multivariate logistic regression models were constructed to study the association between epidural analgesia and SPT, controlling for potential confounders. Additional models studied the association between prolonged second stage and instrumental labor and SPT.
Results: During the study period, 61,308 eligible women gave birth, 31,631 (51.6%) of whom received epidural analgesia. SPT occurred in 0.3% of births. Deliveries with epidural had significantly higher rates of primiparity, induction and augmentation of labor, prolonged second stage of labor, instrumental births and midline episiotomies. The univariate analysis showed a significant association between the use of epidural and SPT (OR: 1.78, 95% CI: 1.34-2.36); however, this association disappeared when parity was introduced (OR: 0.95, 95% CI: 0.69-1.29). Instrumental deliveries and prolonged second stage of labor were both strongly associated with SPT (ORs of 1.82 and 1.77) CONCLUSIONS: Epidural analgesia was not associated with SPT once confounding factors were controlled for.
Keywords: Anal; delivery; labor; lacerations; perineum; sphincter.