We do not know whether repeated doses are better than a single dose

Administering corticosteroids to pregnant women at risk of preterm birth to reduce the severity of neonatal respiratory distress syndrome is an established intervention. The origins of this practice came in 1972 from the pioneering work of Liggins and Howie, who showed a significant reduction in the incidence of respiratory distress syndrome in preterm babies whose mothers had received antenatal corticosteroids.1 These agents are thought to improve surfactant production, and there is also an associated reduction in the risk of neonatal intraventricular haemorrhage, necrotising enterocolitis, hyperbilirubinaemia, and neonatal death. What remains unclear, however, is whether repeat doses should be given if delivery does not occur shortly after the initial course.

Most obstetric units in the United Kingdom administer either betamethasone or dexamethasone as a course of two doses over 24 hours. The evidence for this practice is mainly based on only a single course of antenatal corticosteroids in singleton pregnancies given for up to seven days before delivery and included few multiple pregnancies or …