Fetal lung maturity in complicated pregnancy, as predicted from microviscosity of amniotic fluid.
We measured the microviscosity of amniotic fluid between 28 and 40 weeks of gestation in 252 normal pregnancies and in 172 pregnancies complicated by factors known to influence fetal lung maturation, including chronic high blood pressure, pregnancy-induced hypertension, diabetes mellitus, and therapy with betamethasone. Comparison of the microviscosity value distributions and regression analysis indicated significantly lower microviscosity values in hypertensive disorders, in Class D and Classes F or R diabetes, and after 48 h of treatment with betamethasone. Few changes were observed in Classes A, B, or C diabetes. These observations are consistent with the accelerated maturation of surfactant observed in chronic intrauterine stress and the lower incidence of hyaline membrane disease reported after glucocorticoids.