Very preterm neonates are at increased risk for cortisol insufficiency in acute illness and stress because of immaturity of the adrenal gland.
The adrenal neocortex generally does not synthesize cortisol until ~ 30/40. Before this, the fetus uses progesterone from the placenta to produce cortisol and maternal cortisol crossing the placenta inhibits the fetal hypothalamic-pituitary-adrenal axis.
Low cortisol levels have been associated with hypotension and RDS, hence the logic for using hydrocortisone to treat severe hypotension in very preterm babies.
Previously published: 14/07/14, 01/07/15