Magnesium Sulfate for Prevention of Preterm Birth

(Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.) Practice Pointers Preterm birth, defined as occurring before 37 weeks of gestation, is the leading cause of neonatal death and is associated with several short- and long-term infant morbidities. Magnesium sulfate is one of the most commonly used tocolytics in the United States.1 An earlier pooled analysis of five trials involving 6,145 infants with similar inclusion criteria found a statistically significant benefit of magnesium sulfate as a neuroprotective agent (relative risk [RR] = 0.68; 95% confidence interval [CI], 0.54 to 0.87; number needed to treat = 63).2 This review included 37 studies, with a total of 3,571 women, in which magnesium sulfate was compared with no treatment, placebo, or one of several alternative tocolytic agents. Secondary outcomes included maternal adverse drug reactions and infant admission to the neonatal intensive care unit.