Magnesium sulfate reduces postoperative pain in women with cesarean section: A meta‐analysis of randomized controlled trials

Objectives The use of magnesium sulfate (MgSO 4 ) as an adjunct in different anesthetic regimens for cesarean section (CS) delivery often reports conflicting results. This study aimed to review the effectiveness of MgSO 4 on improving postoperative analgesia after CS systematically. Methods PubMed, Embase, and the Cochrane library were searched for randomized controlled trials (RCTs) published from inception to February 2020. Results A total of 880 women were included (440 in each group). MgSO 4 had a statistically significant effect compared to the control group on the highest VAS (weighted mean difference [WMD] = −0.74, 95% confidence interval [CI] = −1.03 to −0.46, p < 0.001, I 2 = 91.7%, p heterogeneity < 0.001) and the last VAS (WMD = −0.47, 95% CI = −0.71 to −0.23, p < 0.001, I 2 = 95.0%, p heterogeneity < 0.001). MgSO 4 prolonged the time to the first use of analgesia compared to the control group (standardized mean difference [SMD] = −3.03 min, 95% CI = −4.32 to −1.74, p < 0.001, I 2 = 96.3%, p heterogeneity < 0.001). MgSO 4 decreased the consumption of analgesia compared to the control group (SMD = −3.20 mg of IV morphine equivalent, 95% CI: −5.45 to −0.95, p = 0.005, I 2 = 97.6%, p heterogeneity < 0.001). Discussion MgSO 4 decreases the highest VAS in women who underwent general anesthesia, spinal anesthesia, or epidural for CS (all p < 0.05). Additional MgSO 4 significantly reduces postoperative pain in women undergoing CS.