Amniotic fluid analysis in assessment of fetal maturity.

Sixty samples of amniotic fluid were analyzed for their surfactant level by measuring the lecithin-spingomyelin ratio and performing the "shake" test. Cytologic examination of the sediment was also performed using Nile blue sulfate staining. The lecithin-sphingomyelin ratio was found to be the best method to predict fetal maturity and assess the probability of subsequent respiratory distress syndrome. The "shake" test proved to be a valuable screening tool in assessment of fetal pulmonary maturity when the fetus is mature, but of little value when the fetus is immature. The estimation fetal fat cells seemed to be of lesser value in predicting fetal maturity.