Relationship of placental grade to fetal pulmonary maturity and respiratory distress syndrome.

Real-time sonographic placental grading was performed on 215 patients who had amniocentesis for determination of fetal pulmonary maturity between 26 and 42 weeks of gestation. The results of this placental grading were correlated with clinical gestational age and fetal pulmonary maturity, assessed by lecithin-sphingomyelin ratio, phosphatidylglycerol, and the subsequent presence or absence of respiratory distress syndrome. This study showed a statistically significant correlation of placental grade with gestational age, pulmonary maturity, and respiratory distress. Grade 3 placentas were seen in 20% of the cases studied, and in every instance was associated with an absence of subsequent neonatal respiratory distress. Placental grade appeared to be an accurate predictor of fetal pulmonary maturity in the population studied.