Serum unconjugated estriol after intravenous cortisol administration in late pregnancy.

Serum unconjugated estriol levels were measured in 44 pregnant women treated with corticoids for the prevention of respiratory distress syndrome (RDS) in premature infants. Intravenous administration of cortisol (1 g every 6 hours for 24 hours) decreased the level of circulating unconjugated estriol to 40% of the initial value after 6 hours and to 27% after 24 hours. During the 2 succeeding days, all the results remain below the pretreatment values. On the third day, the mean value is no longer different from the control value, but in some patients recovery takes more than 3 days.