Prevention and Tocolytic Agents 2

Preterm birth is the single most important determinant of adverse infant outcomes, in terms of survival and quality of life. Preterm infants are particularly vulnerable to complications with the increasing contribution of neonatal deaths to overall child mortality. Infant mortality and morbidity from preterm birth can be reduced through interventions given to the mother before or during pregnancy, and to the preterm infant after birth. The most beneficial interventions are those that aim to improve outcomes for preterm infants when preterm birth is inevitable. Magnesium sulfate (MgSO4), one of the most commonly used tocolytic agents, has been used in obstetrics for decades, and thousands of women have been enrolled in clinical trials to study the efficacy of prenatal MgSO4 for a variety of conditions including recent studies that demonstrated neuroprotective effects in infants with eclampsia. The uses of MgSO4 in the context of appropriate clinical obstetric practice include fetal neuroprotection before anticipated early preterm (<32 weeks of gestation) delivery. MgSO4 also may be used to prolong the pregnancy to allow for the administration of antenatal corticosteroids between 24 and 34 weeks of gestation.