Phospholipid studies of the amniotic fluid in diabetic pregnancy.

The lecithin/sphingomyelin ration (L/S) of the amniotic fluid is a reliable indicator of fetal lung maturity in most disorders complicating pregnancy. False positive results of L/S occur especially in diabetic pregnancies. Phosphatidylglycerol (PG) improves the ability of the surface active lecithin to prevent lung atelectasis. Respiratory distress syndrome of the newborn infant does not seem to occur when PG is present. By determining PG of the amniotic fluid, false positive L/S can be excluded in diabetic pregnancies.