Obstetrical outcomes of labor with and without analgesia in Robson classification groups 1 and 2a: a single-center retrospective study

Purpose This study aimed to elucidate the effects of neuraxial analgesia on labor in women classified based on the Robson classification system. Methods We retrospectively reviewed the clinical data of singleton cephalic nulliparous deliveries in labor at term between January 2018 and December 2021 and compared obstetrical outcomes between deliveries with and without neuraxial analgesia in women of Robson group 1 (spontaneous labor) and group 2a (induced labor). Statistical analyses were performed using the Wilcoxon ranked-sum test, Fisher’s exact test, and logistic regression model. Statistical significance was set at p < 0.05. Results We identified 2726 deliveries during the period, of which 387 deliveries (215 with analgesia and 172 without analgesia) were in Robson group 1 and 502 deliveries (258 with analgesia and 244 without analgesia) in Robson 2a. In Robson group 1 pregnancies, the cesarean section (CS) rate was higher in those who received analgesia (15%) than in those who did not (3%) ( p = 0.0001). Multivariate analysis revealed that labor with analgesia was a significant risk factor for CS ( p < 0.0001). Similarly, in Robson group 2a pregnancies, we observed a higher CS rate in those with analgesia than in those without analgesia (18 vs. 11%, p = 0.042). Conclusion A higher CS rate was observed in deliveries with analgesia than in those without analgesia both in the Robson group 1 and group 2a pregnancies.