Norepinephrine versus phenylephrine for managing maternal hypotension during cesarean delivery under spinal anesthesia: a meta-analysis of maternal and neonatal outcomes

Abstract

Norepinephrine or phenylephrine administration to prevent and treat hypotension during spinal anesthesia for cesarean section has been a significant topic of discussion. This meta-analysis aimed to update existing evidence and provide further insights into neonatal and maternal outcomes associated with norepinephrine and phenylephrine. Review of randomized controlled trials (RCTs) was performed to assess the effectiveness of norepinephrine and phenylephrine in managing maternal hypotension during cesarean delivery under spinal anesthesia. Neonatal umbilical cord blood pH and maternal hypotension were the primary outcomes. Based on the analysis of 26 RCTs with 2984 participants, we found no significant difference between the norepinephrine and phenylephrine groups in umbilical artery pH in neonates (mean difference (MD) 0.00; 95% confidence interval (CI) −0.00 to 0.01, p = 0.20). Neonates Apgar scores did not differ between both groups. Norepinephrine was associated with lower incidences of bradycardia (risk ratio (RR) 0.44; 95% CI 0.37 to 0.51, p < 0.001) and reactive hypertension (RR 0.53; 95% CI 0.39 to 0.72, p < 0.001) in parturient women than phenylephrine. In neither group did umbilical cord blood levels of partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2) and base excess (BE) levels of neonates differ significantly, nor did maternal hypotension, nausea or vomiting incidence during delivery. For maternal hypotension after spinal anesthesia, norepinephrine and phenylephrine did not significantly differ in neonatal acidemia. Despite similarities to phenylephrine in managing hypotension and maintaining maternal hemodynamic stability, norepinephrine is a promising alternative.