Amniotic fluid phospholipid profile determined by two-dimensional thin-layer chromatography as index of fetal lung maturation.

A phospholipid profile, the main features of which were the lecithin/sphingomyelin (L/S) ratio and the presence or absence of phosphatidylglycerol (PG), was determined in amniotic fluid from 188 patients. There was a mature profile (L/S ratio of at least 2 . 0 and detectable PG) in 145 patients, including seven insulin-dependent diabetics, and noe of their babies developed respiratory distress syndrome (RDS). The L/S ratio was less than 2 . 0 and PG absent in 12 patients, nine of whose babies developed RDS, whereas only three small babies (delivered between 28 and 35 weeks because of fulminant pre-eclampsia or severe abruptio placentae) out of 31 developed RDS when the L/S ratio was less than 2 . 0 but PG was present. When amniotic fluid was collected from the vagina only one out of 69 babies developed RDS when PG was present (regardless of the L/S ratio), while all of seven babies developed RDS when PG was absent. It is concluded that the amniotic fluid phospholipid profile, particularly the presence or absence of PG, gives an accurate assessment of fetal lung maturation. The profile may prove a useful adjunct to the management of high-risk pregnancies, especially after premature membrane rupture and perhaps also when the mother is diabetic.