The relationship of placental grade, fetal lung maturity, and neonatal outcome in normal and complicated pregnancies

Abstract

Ultrasonically diagnosed maturity changes in the placenta, Grades 0 to III, have been previously shown to correlate with fetal lung maturity. In a prospective study of 230 term and preterm complicated pregnancies, we compared the relationship between sonographic placental grading, amniotic fluid phospholipids, and neonatal outcome. The frequencies of gestational age less than 38 weeks, lecithin/sphingomyelin (L/S) ratio less than 2.0, negative phosphatidylglycerol, and neonatal hyaline membrane disease were found to decrease as placental grade advanced from 0 to III. Patients were divided into subgroups on the basis of maternal complications. In patients with Grade III placentas, the frequencies of gestational age less than 38 weeks and L/S ratio less than 2.0 were significantly increased when the subgroup of patients with chronic hypertension was compared individually to both of the subgroups, repeat cesarean section deliveries, and Classes A, B, and C diabetes mellitus (both with p less than 0.05) All three infants who developed hyaline membrane disease in association with Grade III placentas were from pregnancies of less than 38 weeks complicated by chronic hypertension. These findings suggest that the presence of a Grade III placenta is affected by both gestational age and pregnancy complications. Hence, when an elective cesarean section delivery is being planned near term gestation, a Grade III placenta is a reliable predictor of lung maturity. In preterm complicated pregnancies, an ultrasound-diagnosed Grade III placenta may still be associated with hyaline membrane disease.