General Anesthesia Associated With Increased Severe Postpartum Hemorrhage Risk Compared to Neuraxial Anesthesia in Cesarean Deliveries

Based on the hypothesis that the effect of general anesthesia (GA) vs. neuraxial anesthesia (NA) on postpartum hemorrhage (PPH) varies according to its underlying etiology, this study aimed to investigate the impact of the anesthetic technique on the risk of severe PPH indistinct clinical scenarios: (1) emergency cesarean deliveries at risk for uterine atony and (2) cases of placenta accreta spectrum (PAS) at risk for massive surgical hemorrhage. In this retrospective dual-cohort study, patients receiving GA in Cohort 1 were matched 1:3 to NA patients using propensity score matching (PSM). Cohort 2 comprised patients with PAS who underwent scheduled cesarean hysterectomy. The primary endpoint was severe PPH, and the results were analyzed statistically. In the matched Cohort 1 (n = 600), the incidence of severe PPH was significantly higher in the GA group compared to the NA group (21.3 vs. 9.8%). After adjusting for operative duration and tranexamic acid use, GA was independently associated with an almost threefold increased risk of severe PPH [Adjusted Odds Ratio (aOR): 2.91; 95% Confidence Interval (CI): 1.80–4.69; p < 0.001]. In contrast, in Cohort 2 (n = 75), the rate of severe PPH was high in both groups, with no significant difference observed (91.1 vs. 86.7%; p > 0.05). However, post-hoc Bayesian analysis indicated a > 99 and 91% probability that GA is associated with increased blood loss in Cohort 1 and Cohort 2, respectively. In our matched cohort, general anesthesia was associated with an almost threefold increase in the risk of severe PPH in emergency cesarean deliveries susceptible to uterine atony. In cases such as the placenta accreta spectrum, the primary determinant of hemorrhage is the underlying surgical pathology, and the role of anesthetic management appears to be secondary. However, these findings for the PAS cohort should be considered exploratory due to the small sample size. In general, these results strongly support the personalization of anesthetic strategies based on the expected etiology of hemorrhage to reduce maternal morbidity and mortality.