Does meperidine analgesia affect the incidence of obstetric lacerations at vaginal delivery?

Purpose: To study whether meperidine analgesia affects the incidence of obstetric lacerations at normal vaginal deliveries. Materials and methods: A retrospective cohort study of all women with term vertex singleton pregnancies, who underwent normal vaginal deliveries, in a single tertiary hospital, between 2011 and 2015, was performed. The incidence of various obstetric lacerations was compared between deliveries with meperidine analgesia and deliveries with no analgesia. Deliveries with epidural analgesia and instrumental deliveries were excluded. An intravenous infusion of 75 mg of meperidine was administered together with 25 mg of promethazine. A multivariate logistic regression analysis was performed to assess the association between meperidine analgesia and obstetric lacerations, after controlling for confounders. Results: Overall, 5227 (91.8%) deliveries with no analgesia and 466 (8.1%) deliveries with meperidine analgesia were included. Meperidine analgesia was associated with a decreased risk of first- and second-degree perineal lacerations (adjusted OR = 0.63, 95% CI = 0.49–0.81), and a decreased risk of any suturing (adjusted OR = 0.73, 95% CI = 0.59–0.91), after controlling for confounders. Meperidine analgesia did not affect the risk of severe perineal lacerations or episiotomies. Conclusion: Meperidine analgesia may have a protective effect against first- and second-degree perineal lacerations.