Amniotic fluid cortisol in normal and diabetic pregnant women and its relation to respiratory disease in the neonate.

One hundred and thirty samples of amniotic fluid from normal and diabetic pregnant women were analyzed for cortisol concentration. In normal pregnancies, cortisol was present in low concentrations until 35 weeks' gestation, followed by a sharp rise at 36 weeks and a continued upward trend to 39 weeks. The rise after 35 weeks was delayed or absent in many patients with diabetes. In the combined population, the incidence of respiratory disease with a lecithin/sphingomyelin ratio greater than or equal to 2 was 26 per cent if the amniotic fluid cortisol was less than 4.3 microgram per 100 ml. and 2.9 per cent if the cortisol concentration was greater than or equal to 4.3 microgram per 100 ml.