Antenatal corticosteroids: the good, the bad and the unknown.

PURPOSE OF REVIEW: The purpose of this review was to summarize recently published clinical and animal-based studies of antenatal corticosteroids, describe current recommendations for practice, and suggest priority areas for future research.

RECENT FINDINGS: A single course of antenatal corticosteroids is known to improve newborn lung function after preterm birth and to reduce the risk of newborn death. Current evidence from animal and clinical studies suggests that additional numbers of courses do not further improve lung function and are associated with risks of adverse consequences. These risks principally include restricted intrauterine growth, altered brain development, postnatal insulin resistance and changes to the hypothalamic-pituitary-adrenal axis.

SUMMARY: The research challenges in this field are now centred on uncovering the mechanisms by which cortisol is involved in programming the fetus for its future metabolic life, and discovering ways in which the effectiveness and safety of antenatal glucocorticoids can be enhanced.