Antenatal Magnesium Sulfate and Neurologic Outcome in Preterm Infants

OBJECTIVE: To systematically review rates of neurologic outcomes reported in childhood for the preterm fetus exposed to antenatal magnesium sulfate. DATA SOURCES: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, CENTRAL (The Cochrane Library 2008, Issue 3), relevant references from retrieved articles, and abstracts submitted to major congresses. METHODS OF STUDY SELECTION: We sought all randomized controlled trials (RCTs) of antenatal magnesium sulfate with neurologic outcomes reported for the fetus. TABULATION, INTEGRATION, AND RESULTS: Five eligible RCTs with 6,145 fetuses were identified; in four studies (4,446 fetuses) the primary intent was neuroprotection of the fetus. Methods of the Cochrane Collaboration were used to analyze the data. Antenatal magnesium sulfate therapy given to women at risk of preterm birth substantially reduced the risk of cerebral palsy in their children (relative risk [RR] 0.69; 95% confidence interval [CI] 0.54-0.87; five trials; 6,145 infants). The number needed to treat to prevent one case of cerebral palsy was 63 (95% Cl 43-155). Moreover, there was a significant reduction in the rate of substantial gross motor dysfunction (RR 0.61; 95% Cl 0.44-0.85; four trials; 5,980 infants). No statistically significant effect of antenatal magnesium sulfate therapy was detected on pediatric mortality (RR 1.01; 95% Cl 0.82-1.23; five trials; 6,145 infants), or on other neurologic impairments or disabilities in the first few years of life. There were no significant effects of antenatal magnesium sulfate on combined rates of mortality with neurologic outcomes, except in the studies where the primary intent was neuroprotection, where there was a reduction in death or cerebral palsy (RR 0.85; 95% Cl 0.74-0.98; four trials; 4,446 infants). CONCLUSION: Antenatal magnesium sulfate therapy given to women at risk of preterm birth is neuroprotective against motor disorders in childhood for the preterm fetus. (Obstet Gynecol 2009;113:1327-33)