Optimizing antenatal corticosteroid therapy.

Treatment with antenatal corticosteroids (ACS) is standard of care for women at risk of preterm birth between 24 and 34 weeks' gestation. ACS are increasingly used for other indications, including threated or indicated late preterm birth, elective cesarean, and in at-risk pregnancies for periviable gestations. However, the various drugs and doses being used worldwide have not been rigorously evaluated to optimize clinical responses and to minimize potential risks. Translational research in animal models indicate that a constant, low concentration fetal exposure to ACS is sufficient for lung maturation, resulting in lower fetal exposures. Clinical trials to develop dosing strategies with inexpensive and widely available drugs could promote greater use in low resource environments.