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Randomized Controlled Trial
. 2025 Sep 2:19:7571-7580.
doi: 10.2147/DDDT.S535671. eCollection 2025.

Norepinephrine or Phenylephrine to Prevent Spinal Anesthesia-Induced Hypotension During Cesarean Section: A Double-Blinded, Randomized, Controlled Study of Fetal Cerebral Perfusion

Jinping Liu #  1 , Zhimin Sheng #  2 , Feihe Guo  1 , Xiao Lin  1 , Li Xu  3 , Lihong Sun  1 , Xiaowei Qian  1
Affiliations
Randomized Controlled Trial

Norepinephrine or Phenylephrine to Prevent Spinal Anesthesia-Induced Hypotension During Cesarean Section: A Double-Blinded, Randomized, Controlled Study of Fetal Cerebral Perfusion

Jinping Liu et al. Drug Des Devel Ther. .

Abstract

Purpose: Spinal anesthesia-induced hypotension can cause detrimental effects on both the mother and the fetus, and it remains a significant concern in obstetric anesthesia. The use of vasopressors is considered the most reliable and effective approach. Previous studies have shown that norepinephrine appears to be superior to phenylephrine in maintaining maternal heart rate and cardiac output. Therefore, we hypothesize that norepinephrine is more effective than phenylephrine in maintaining neonatal cerebral perfusion when used to prevent spinal anesthesia-induced hypotension.

Patients and methods: This study is a prospective, double-blinded, randomized trial. We enrolled 216 singleton parturients who were scheduled for elective cesarean delivery. The patients received a prophylactic intravenous infusion of either norepinephrine (0.08 μg/kg/min) or phenylephrine (0.5 μg/kg/min). Maternal cardiac output was not routinely monitored during the study period. Fetal ultrasound examinations were performed, with blood velocity measured in the middle cerebral artery and umbilical artery, and the cerebroplacental ratio calculated.

Results: Ninety subjects were ultimately analyzed in each group. The changes in blood velocity in the middle cerebral artery and umbilical artery, as well as the calculated cerebroplacental ratio at 3 and 6 minutes after spinal anesthesia, did not differ significantly between the two groups. The estimated difference of ΔCPR in two groups was - 0.01 (95% CI, -0.05-0.02, P = 0.491) at 3 minutes and was 0.02 (95% CI, -0.01-0.07, P = 0.204) at 6 minutes.

Conclusion: Prophylactic infusion of norepinephrine or phenylephrine at comparable doses has similar effects on fetal cerebral perfusion.

Keywords: fetal cerebral perfusion; hypotension; norepinephrine; phenylephrine.

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Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Consolidated Standards of Reporting Trials (CONSORT) flowchart showing patient recruitment.
Figure 2
Figure 2
Cerebroplacental Ratio (CPR) Trends Following Spinal Anesthesia. The chart illustrates changes in CPR at 0 min (baseline), 3 min and 6min after spinal anesthesia.
See this image and copyright information in PMC

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