Amniotic fluid phospholipid analysis in normal and complicated pregnancies.

Amniotic fluid lecithin/sphingomyelin (L/S) ratios were determined at least once in 190 pregnancies. In 127 pregnancies an amniotic fluid specimen was obtained within 72 hours of delivery. This constitutes the corrected group. Respiratory distress was encountered 21 times with 13 of these being clinical hyaline membrane disease (CHMD). The remaining cases were either transient respiratory distress or felt to be aspiration pneumonia. When the L/S ratio was positive and the infant delivered vaginally, there was only one case of CHMD. However, when the patients had grave enough disease to warrant cesarean section, CHMD was encountered in seven cases out of 68 cesarean sections. Of the eight cases of CHMD, five were in mothers whose pregnancy was complicated by diabetes mellitus.