Effect of Prophylactic Phenylephrine Infusion Versus Interventional Ephedrine Boluses on Umbilical Blood pH in Cesarean Deliveries Under Spinal Anesthesia: A Retrospective Case-Control Study.

Hypotension is a common complication of spinal anesthesia for cesarean section. Although phenylephrine has replaced ephedrine as the first-line vasopressor, comparative data on neonatal outcomes remain important in clinical decision-making. The objective of this study was to compare the effects of prophylactic phenylephrine infusion versus interventional ephedrine boluses on umbilical artery pH and maternal hemodynamic stability in women undergoing cesarean section under spinal anesthesia. In this retrospective case-control study we analyzed perioperative and neonatal data of elective cesarian section cases where either ephedrine boluses (total dose of more than 15 mg) or prophylactic phenylephrine infusion were employed for blood pressure control following spinal anesthesia. Demographic, hemodynamic, obstetric and neonatal data were extracted from medical records. Ninety-four elective cesarean section cases were included. Umbilical artery pH, base excess, and Apgar scores were assessed as primary and secondary neonatal outcomes. The lowest recorded systolic blood pressure (SBP), mean arterial pressure (MAP), and incidence of nausea and vomiting were evaluated as maternal outcomes. Umbilical artery pH and other blood gas parameters did not differ significantly between groups. Neonatal acidosis (pH < 7.2) occurred in two cases in the ephedrine group while none were noted in the phenylephrine group. Maternal hemodynamic stability was significantly better in the phenylephrine group, with higher nadir SBP and MAP ( < 0.001). Nausea was more common with ephedrine (42.5% vs. 10.6%, < 0.001), and vomiting occurred only in this group. Prophylactic phenylephrine infusion provides superior maternal hemodynamic stability and better tolerance during cesarean delivery compared to interventional ephedrine boluses, without change in neonatal acid-base status.