[Assessment of fetal lung maturity by determination of phosphatidylglycerol in human amniotic fluid].

The enzymatic method for the specific quantification of phosphatidylglycerol (PG) and phosphatidylcholine (PC) was described in detail in this paper. Under the present assay conditions, as little as 2 nmoles of PG or PC was accurately measured. The possibility of contamination of cardiolipin and bilirubin in amniotic fluid was eliminated by chromatography on a silicic acid column. Using 275 amniotic fluid samples from uneventful pregnancies, fetal lung maturity was assessed by using a variety of parameters including PG and PC determination. Based on the results of the present investigation, critical concentrations of PG and PC were determined to be 0.36 and 3.0 mumoles/dl, respectively. 239 infants who had more than the critical PG concentration were all associated with normal respiratory function except 3 cases (false-positive rate, 1.3%). 30 out of 36 infants with a PG value lower than this level developed respiratory distress syndrome after birth (false-negative rate, 16.7%). These results indicated that the PG determination was the most accurate predictor of fetal lung well-being prior to birth among the clinical tests so far reported.