The current dose and schedule for antenatal corticosteroids (ACS) follows the original publication by Liggins and Howie in 1972. That dose and schedule was based on sheep models from the 1960s. The dose in current use had never been evaluated to minimize exposures while assuring efficacy. New pharmacokinetic and pharmacodynamic data is calling into question whether the current dose and schedule is necessary. 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. In this episode, we will summarize a new clinical commentary published in AJOG in March 2024 highlighting the current state and controversies regarding ACS for threatened preterm labor.
