Dystocia and analgesia: which came first? Time of choice of neuraxial labor analgesia and obstetric outcomes: a community-based retrospective cohort study

Background: Neuraxial labor analgesia (NLA) has long been considered a risk factor for cesarean and vacuum delivery. We aim to investigate if, as suggested in the literature, these adverse outcomes are rather associated with a dystocic painful labor prompting an NLA request. Methods: This community-based cohort study was conducted from January 2010 to March 2023 in a Baby Friendly Hospital which supports physiological childbirth. Nulliparous women who received NLA (n = 1905) were divided into 2 groups according to whether they chose to request NLA a priori (before experiencing labor pain; AP group, n = 395) or in labor (after experiencing labor pain; IL group, n = 1510). A descriptive analysis of the sample was performed. The primary outcome was mode of delivery. A multinomial logistic regression model was used to assess in-labor request as a possible predictor of vacuum extraction and cesarean delivery, considering maternal age, height, and BMI as confounders. Results: Groups differed in median maternal age (31 vs 30 years AP vs IL, respectively P < 0.001) and neonatal weight (3195 vs 3270, P < 0.007). The risk of cesarean delivery was higher in the IL group (RRR 2.35; 95% CI 1.70 to 3.23; P < 0.001), while that of vacuum extraction was comparable between the two groups (RRR 0.81; 95% CI 0.53 to 1.21; P = 0.293). Conclusions: The higher incidence of cesarean delivery in the IL group compared to the AP group suggests that many women asking for NLA in labor have underlying risk factors for cesarean delivery: the relationship between NLA and cesarean delivery might not be causal. The association with vacuum remains less clear.