Single versus repeat courses of antenatal steroids to improve neonatal outcomes: risks and benefits.

Recent additions to the literature provide evidence supporting the use of repeat courses of antenatal steroids. Both human and animal studies offer evidence that repeat courses of corticosteroids improve neonatal pulmonary outcomes, especially for the infants delivered at earlier gestational ages. Although there is also evidence to suggest altered neuronal maturation and intrauterine growth restriction in animals treated with repeat steroids, randomized controlled studies in humans have shown that birth weight reduction was only seen in those infants treated with 4 or more courses of corticosteroids. In addition, the reduction in neonatal birth weight and head circumference seen after multiple courses of antenatal corticosteroids normalizes by the time of hospital discharge. Studies are ongoing to investigate the 24-month post delivery physical and neurodevelopmental outcomes in infants exposed to repeat courses of antenatal corticosteroids. Although there is evidence demonstrating the safety of a single repeat, or 'rescue', dose of antenatal corticosteroids, this must be tempered against the adverse effects seen after multiple courses of weekly repeat steroids. Randomized controlled trials are needed to determine the optimal number of courses of antenatal steroids to reduce the frequency of neonatal respiratory distress syndrome (RDS) without adversely affecting other neonatal outcomes.