Neonatal stress and resilience - lasting effects of antenatal corticosteroids 1.

Antenatal corticosteroids (ACS) are standard of care for women at risk of preterm delivery between 24 and 34 weeks gestation. Their use decreases preterm morbidities and mortality. However, ACS treatments mimic a stress response by increasing fetal steroid levels at early gestational ages when the fetus is normally protected from high glucocorticoid levels. Within the context of concept of the developmental origins of adult health and disease, ACS are effective stressors in fetal animal models that alter developmental programs and outcome in adult animals. Although few short-term adverse effects of ACS in infants and children are apparent, there are cohort studies demonstrating cognitive, metabolic, and cardiovascular effects in humans beyond 30 years of age. ACS likely interact with other stresses - maternal diseases complicating prematurity, premature delivery, and nutritional deficiencies - to program outcomes that may not be known for many years. The risks of ACS will increase as indications for ACS increase to late gestation preterm infants and possibly Cesarean-section deliveries.