The differential role of anesthetic technique by etiology of postpartum hemorrhage: a dual-cohort analysis of emergency cesarean delivery and placenta accreta spectrum

Objective: 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. Methods: 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. Results: Bayesian analysis indicated a > 99 and 91% probability that GA is associated with increased blood loss in Cohort 1 and Cohort 2, respectively. Conclusion: 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.