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. There were 10 cases of grade I and 22 cases of grade II placenta in the series. There was one mature L/S ratio in each placental grade; both had intermediate results with Clements' test. These findings differ significantly from those published in the literature on the subject, which are based on investigations in more mature fetal populations.