Tocolytics for Delaying Preterm Birth

Introduction to Tocolytic Therapy

The American College of Obstetricians and Gynecologists recommends tocolytic therapy to delay delivery for 48-72 hours to allow for administration of antenatal corticosteroids and maternal transfer to a tertiary care facility with appropriate neonatal intensive care capabilities 1
Tocolytic therapy with nifedipine and indomethacin may delay delivery between 48 and 72 hours in women with preterm labor and intact membranes after 26 weeks of gestation 1, 2, 3

Magnesium sulfate is used as a tocolytic, with its primary benefit in the periviable period being for fetal neuroprotection, and it reduces the incidence of cerebral palsy when administered before anticipated early preterm birth 1, 2, 3, 4, 5
The American College of Obstetricians and Gynecologists suggests that tocolytic therapy should be considered when gestational age is between 24-34 weeks, and there is a need to administer antenatal corticosteroids 1
Tocolytic therapy is generally not recommended in preterm labor with intact membranes when antibiotics are being considered, or in cases where delivery would be beneficial for maternal or fetal indications 1, 2, 6

Despite their ability to delay delivery temporarily, no tocolytic has been consistently shown to improve neonatal outcomes or reduce the overall rate of preterm birth 1
The primary benefit of tocolytics is to gain time for corticosteroid administration and maternal transfer, and the choice of tocolytic should consider gestational age, maternal comorbidities, and fetal status 1, 3