Effect of diabetes mellitus on amniotic fluid lecithin/sphingomyelin ratio and respiratory distress syndrome.

Ninety-eight insulin-dependent diabetic patients were cared for during 108 pregnancies following an ambulatory program aimed at close control of blood sugar levels. The incidence of respiratory distress syndrome (RDS) in these patients was not different from that in nondiabetic patients. Fetal pulmonary maturity seemed to progress at a normal rate as evidenced by an equal incidence of mature lecithin/sphingomyelin (L/S) ratios at various stages of gestation in diabetic and nondiabetic patients. There was no evidence that Class B and C diabetic patients have delayed fetal lung maturation or that Class E, F, and R patients have accelerated maturation. It is concluded that careful metabolic control of the pregnant diabetic patient results in a normal process of fetal pulmonary maturation without increased risk of RDS.