Efficacy and safety of norepinephrine versus phenylephrine for post-spinal hypotension in preeclamptic patients: A systematic review and meta-analysis

Objective: We conducted a systematic review and meta-analysis to evaluate the fetomaternal outcomes after the administration of norepinephrine or phenylephrine for the treatment of post spinal hypotension in preeclamptic women undergoing a cesarean section. Data sources: We searched on PubMed, Embase, Scopus, Cochrane CENTRAL, and clinicaltrials.gov from inception till June 2024. Study selection: Randomized controlled trials of preeclamptic women receiving norepinephrine or phenylephrine for post spinal hypotension were included. Data extraction and synthesis: Two reviewers extracted data onto an Excel spreadsheet. R version 4.4 was used for statistical analysis. Risk ratios (RR) and their 95% confidence intervals (CIs) were calculated and pooled using the random effects model. Cochrane's risk of bias (RoB 2) tool was used for quality assessment. This review has been registered with PROSPERO (CRD42024532740). Results: A total of 4 trials, comprising 413 participants, were included in this review. 206 patients received norepinephrine, while 207 received phenylephrine. The incidence of maternal bradycardia was significantly lower in the norepinephrine group compared with the phenylephrine group (RR = 0.25, 95 % CI = 0.16 to 0.39, p < 0.01). There were no statistical differences in other maternal outcomes or in the umbilical artery and umbilical vein blood gas analysis values. We also analyzed adverse events such as nausea (RR = 1.00, 95 % CI: 0.62 to 1.60, p = 1.00) and vomiting (RR = 0.99, 95 % CI: 0.89 to 1.11, p = 0.61), but they did not show a significant association with any group. All the trials had a moderate or low risk of bias. Conclusion: Bolus doses of NE and PE for the treatment of post-spinal hypotension in preeclamptic women undergoing cesarean sections were found to exhibit comparable neonatal outcomes. However, NE provided superior maternal safety due to a lower incidence of bradycardia compared to PE.