Antenatal steroids for fetal lung maturity: Time to target more frequent doses to fewer women?

Antenatal corticosteroids for fetal lung maturation have become mainstay treatment in women thought to be at high-risk of premature birth. To ensure treatment efficacy before delivery, the current practice is to administer steroids early to a woman considered at risk; however, neonatal benefit is lost after the seven-day treatment-to-delivery window. Over half of women who deliver before 34 weeks' gestation do not receive antenatal corticosteroids within this timeframe, but many still deliver prematurely; however, clinicians are reluctant to administer repeated courses of steroids due to concerns, among others, of impaired fetal growth. However, evidence is mounting regarding the optimal timing for steroids, including substantive benefits close to delivery, and the benefits of repeated courses if delivery has not occurred. Better targeted treatment is required to allow for maximum benefit; reducing unnecessary treatment in low-risk women, while targeting therapy in the high-risk cohort and offering repeat courses if the seven-day window is exceeded. Novel tools to aid prediction may help implement this strategy.