Maternal and fetal outcomes of phenylephrine bolus versus infusion during cesarean delivery: A systematic review, meta-analysis, and trial sequential analysis

Abstract Background and Aims: Phenylephrine is widely used to manage postspinal hypotension during cesarean delivery under neuraxial anesthesia. However, the optimal method of administration, bolus or infusion, remains uncertain. Material and Methods: This systematic review and meta-analysis (PROSPERO CRD420251081996) included randomized controlled trials comparing phenylephrine bolus and infusion regimens during cesarean delivery. The primary outcome was maternal hypotension. Secondary outcomes included reactive hypertension, bradycardia, intraoperative nausea and vomiting, and neonatal outcomes such as Apgar scores, umbilical arterial pH, and paO 2 . A random-effects model was used for meta-analysis, and trial sequential analysis (TSA) was performed to evaluate the robustness of the evidence. Results: Twenty randomized controlled trials involving 2742 parturients (bolus n = 1314; infusion n = 1428) were included. Overall, there was no significant difference in predelivery hypotension between infusion and bolus regimens (RR 0.95, 95% CI 0.70–1.30; I² =94%). However, in a subgroup of fixed-rate infusions, a reduction in hypotension was observed compared with bolus (RR 0.73; 95% CI 0.61–0.88). Infusion was associated with a higher risk of reactive hypertension, while bradycardia and other maternal outcomes were similar. Although Apgar scores and UA pH showed minor statistical differences, all neonatal values remained within normal clinical ranges. TSA confirmed sufficient evidence only for the fixed-rate infusion subgroup; the overall pooled estimate remained inconclusive. Conclusions: Phenylephrine infusion, particularly fixed-rate prophylactic infusion, may reduce hypotension, but the overall evidence does not demonstrate superiority over bolus dosing. Given the very high heterogeneity and increased reactive hypertension with infusion, results should be interpreted cautiously. Neonatal outcomes were clinically comparable between groups.