Efficacy and safety of different vasopressor infusions on feto-maternal outcomes in normotensive patients undergoing caesarean delivery: a systematic review and network meta-analysis of randomised controlled trials.

Summary

Across 55 RCTs (n=5,487), continuous infusions of alpha-agonists with mild beta activity (norepinephrine, metaraminol) and phenylephrine reduced maternal hypotension compared with no infusion. Mephentermine and metaraminol better preserved umbilical arterial and venous acid–base status than comparators. Findings support norepinephrine or metaraminol over ephedrine for prophylaxis, though fetal outcome evidence remains comparatively sparse.

Key Findings

• Four vasopressors (metaraminol, norepinephrine, phenylephrine, adrenaline) were definitively superior to no infusion for preventing maternal hypotension.
• Mephentermine and metaraminol better preserved umbilical arterial and venous acid–base balance compared with alternatives.
• Alpha-agonists with mild beta activity outperformed ephedrine for maternal hemodynamic stability; fetal outcome evidence is less robust.

Clinical Implications

For prophylaxis of spinal-induced hypotension during cesarean delivery, norepinephrine or metaraminol infusions should be considered first-line over ephedrine, balancing maternal hemodynamics and neonatal acid–base status. Phenylephrine remains effective, but agents with mild beta activity may reduce bradycardia and improve fetal acid–base balance.

Limitations

• Heterogeneity in dosing regimens and infusion protocols across trials
• Limited high-certainty evidence for neonatal outcomes compared with maternal endpoints

Future Directions

Head-to-head RCTs comparing norepinephrine vs phenylephrine and metaraminol with standardized dosing, with adequately powered neonatal outcomes, are warranted.