ACTH levels in maternal, fetal and neonatal plasma after short-term prenatal dexamethasone therapy.

The effect of prenatal dexamethasone therapy (12, 8 and 4 mg doses given intramuscularly on three consecutive days) on ACTH levels in maternal plasma (n=33), mixed umbilical cord plasma (n=31) and plasma from the newborn (n=29) was studied, and the results were compared with those obtained in 56 healthy parturients and 50 of their newborn. Maternal ACTH after delivery was significantly lower in the mothers treated with dexamethasone than in the control group. Cord ACTH values were similar in the two groups. ACTH levels fell during the early neonatal period, but only at 12 to 24 hours were the ACTH levels significantly lower in the dexamethasone group than in the controls. Gestational age, birth weight and the interval between the dexamethasone therapy and delivery had no significant effect on cord ACTH levels. Short-term prenatal dexamethasone therapy seemed to have very little effect on ACTH secretion in the mother, in the fetus and in the newborn.