Which Tocolytic Is Best for Inhibiting Preterm Labor?

Preterm labor resulting in birth between 23 and 34 weeks' gestation is a major cause of neonatal morbidity and mortality; thus, it is strongly recommended that all women with threatened preterm birth receive glucocorticoids at least 48 hours prior to birth to advance fetal development and reduce adverse neonatal outcomes. Tocolytics may help to inhibit uterine contractions, thereby lowering risk for preterm birth during the 48-hour window following glucocorticoid initiation. To compare the efficacy of the tocolytics nifedipine (a calcium-channel blocker) and atosiban (an oxytocin receptor antagonist; not available in the U.S.), Dutch investigators randomized 510 women in preterm labor to receive either agent at standard doses. The primary o…