Tocolysis: A Review of the Literature.

IMPORTANCE: Preterm delivery represents an important cause of infant morbidity and mortality. Various tocolytics have been studied with the objective of stopping preterm labor, increasing gestational age at delivery, and preventing complications related to preterm birth.

OBJECTIVE: This review aims to summarize the major classes of tocolytics and review the evidence regarding use of each.

EVIDENCE ACQUISITION: A PubMed search of the following terms was performed to gather relevant data: "tocolytic," "preterm labor," "preterm delivery," "PPROM," "magnesium," "indomethacin," "nifedipine," and "betamimetics."

RESULTS: The benefits and risks of nonsteroid anti-inflammatory drugs, calcium channel blockers, magnesium, and betamimetics are reviewed. Calcium channel blockers afford superior outcomes in terms of prolonging gestation and decreasing neonatal morbidity and mortality with the fewest adverse effects.

CONCLUSIONS AND RELEVANCE: Tocolytics, particularly calcium channel blockers, may provide benefit to pregnant women and their infants. Their use should be tailored to the particular clinical circumstances of the patient and used in conjunction with other management strategies ( e.g. , administration of corticosteroids for fetal lung maturation or magnesium for neuroprotection and transfer to a tertiary medical center). Further research and professional guidelines are needed on optimal use of these agents.