Placental grade and pulmonary maturity in premature fetuses.

The correlation between the placental echographic appearances and pulmonary maturity was studied in 32 cases of normal pregnancy between the 29th and 33d weeks. The placental appearance was classified according to Grannum's criteria, and an amniocentesis was performed in each case. Both an L/S ratio and a foam stability (Clements') test were performed on the amniotic fluid.