Antenatal corticosteroids for fetal lung maturation in threatened preterm delivery: indications and administration

Antenatal maternal administration of corticosteroids has been shown to reduce morbidity and mortality rates in preterm delivery. Threatened spontaneous or medically indicated preterm delivery for maternal or fetal indications between 24 and 34 weeks of gestation with unknown fetal lung maturity status are indications for antenatal corticosteroid administration. Recent studies have challenged current practice of antenatal glucocorticoid use. The goal of this expert letter is to provide recommendations based for the clinical use of antenatal glucocorticoids based on the current evidence from published studies.

The published literature (PubMed search), as well as the recommendations of other national societies, has been searched and taken into consideration for these recommendations.

The standard regimen of antenatal corticosteroids involves a single course of 2 × 12 mg betamethasone administered intramuscularly within 24 h. The administration of corticosteroids usually is performed between 24 and 34 weeks gestation. However, under particular circumstances it may be beneficial even at 23 weeks and at 35-36 weeks of gestation. The evidence to date is clearly against the routine administration of multiple antenatal steroid courses. In special clinical situations, a second course of betamethasone ("rescue course") may be justifiable. Tocolysis during administration of steroids is not routinely indicated in the absence of contractions, cervical shortening or rupture of membranes.