Fetomaternal outcomes among cesarean section parturients administered with norepinephrine vs. phenylephrine for post-spinal anesthesia hypotension: A systematic review and meta-analysis

Post-spinal anesthesia hypotension during cesarean delivery poses significant risks to maternal cardiac output and fetal oxygenation. Although phenylephrine (PE) is the standard vasopressor, its use is linked to an increased incidence of maternal bradycardia. In contrast, norepinephrine (NE) offers a more favorable hemodynamic profile and is emerging as a promising alternative. This systematic review and meta-analysis of 18 randomized controlled trials compared NE and PE for the prevention and treatment of post-spinal hypotension in cesarean section parturients. Our findings demonstrate that while NE and PE are equally effective in managing hypotension, NE significantly reduces the incidence of maternal bradycardia (OR = 0.49 [CI: 0.38 to 0.62]) and shows a trend toward fewer adverse maternal events, such as dizziness and reactive hypertension. Additionally, neonatal outcomes indicated a lower birth weight with NE--although still within the normal range--along with tendencies toward lower umbilical arterial lactate levels and improved umbilical vein blood gas pH. These results support NE as a viable alternative to PE, particularly for lowering the incidence of maternal bradycardia, and provide crucial evidence for updating clinical practice guidelines to enhance maternal and neonatal care during cesarean deliveries. Systematic review registration ID: CRD42024593459https://www.crd.york.ac.uk/PROSPERO/view/CRD42024593459