Respiratory distress syndrome with mature lecithin/sphingomyelin ratios: diabetes mellitus and low Apgar scores.

A detailed study was made of 150 women delivered of their infants within 72 hours of an amniocentesis where the lecithin/sphingomyelin (L/S) ratio was 2.0 or greater. There were nine neonates with respiratory distress (6.0 per cent). There were two neonatal deaths, both due to severe congenital heart disease. A mature amniotic fluid L/S ratio predicts a newborn infant who will not have respiratory distress syndrome (RDS) in most pregnancies. There is a significantly increased risk of RDS in neonates with a mature L/S ratio if the mother has insulin-dependent diabetes or if there is a resulting low Apgar score. The method of delivery (cesarean section or vaginal) does not affect the frequency of RDS where the L/S ratio is 2.0 or more.