Planned vaginal birth with epidural analgesia in obese women: effects on maternal and fetal outcomes. A retrospective cohort study

Background Obese pregnant women (body mass index ≥ 30 kg/m 2 ) often receive epidural analgesia (EA) during their deliveries. However, there is scarce evidence on the effect of EA on maternal and perinatal outcomes in these women. The goal of this study is to evaluate outcomes in obese women receiving EA during their planned vaginal deliveries. Methods Patient records of obese women undergoing a planned vaginal delivery from January 2018 until December 2023 in a tertiary care center were screened. Women were stratified into two groups depending on whether or not they received EA during their deliveries. EA was provided after shared decision making between provider and mother. Baseline characteristics and perinatal outcomes were collected for both groups. Primary outcomes were conversion to cesarean section (CS) and reduced Apgar scores (<7 at 5 minutes). Secondary outcomes were mode of delivery, type of anesthesia, estimated blood loss, episiotomies, perineal ruptures, hospital length of stay, fetal umbilical artery pH and base excess. Using inverse probability of treatment weights, primary outcomes per group were adjusted for baseline characteristics in a logistic regression model. Results 259 women received EA, 144 did not. Women with EA had lower gravidity and parity, more often induction of labor and delivered children with higher birthweights. In total 88 (22%) women in both groups required secondary CS. General anesthesia was avoided for all 64 women with EA. In the non-EA group, general anesthesia was used for seven out of 24 women. After adjustment, conversion to CS (OR 0.984, CI 0.542 to 1.786, P=0.957) and reduced Apgar scores (OR 1.138, CI 0.375 to 3.458, P=0.820) were not significantly different. Secondary outcomes (unadjusted) showed several differences. EA was associated with more vacuum deliveries (16% vs 2%, P<0.001), more episiotomies (18% vs 7%, P=0.003), higher mean blood loss (523 ml vs 351 ml, P<0.001), and longer mean length of hospital admittance (4.3 days vs 3.5, P<0.001). Conclusions Women with a BMI ≥ 30 kg/m 2 receiving EA for planned vaginal delivery showed similar conversion to CS and similar Apgar scores, when compared to obese women without EA. Secondary maternal outcomes were less beneficial for the group receiving EA, but fetal outcomes were not. When conversion to surgical delivery was required, general anesthesia was avoided in 100% of women with EA, while 29% of women without EA required general anesthesia, although fetal outcomes were not worse in this group. In conclusion, early epidural placement for intended vaginal delivery in obese women is safe for mother and child and may prevent the need for general anesthesia for conversion to CS.