[Current methods of prenatal determination of lung maturity of the infant from amniotic fluid]

Two currently used methods of determining fetal pulmonary maturity were verified on the basis of 148 amniotic fluid samples: one dimensional sequential thin-layer chromatographic determination of the lecithin: sphingomyelin ratio and of phosphatidyl glycerol, and an immunologic slide detection of phosphatidyl glycerol (Amniostat-FLM). With both methods, which have the advantage that they can be performed quickly and can sometimes even be used at the bedside (Amniostat-FLM), a respiratory distress syndrome in the newborn can be ruled out with a high degree of confidence if the threshold values are exceeded (L/S greater than 2; phosphatidyl glycerol present). As with all historical methods, the positive correctness of these two modern methods (no RDS if the child is born within 72 hours despite a negative phosphatidyl glycerol test in the amniotic fluid) is low. Clearly, apart from the quantitative existence of certain surfactant phospholipids (lecithin, phosphatidyl glycerol), there are other perinatal events or measures which determine the extent and severity of RDS in the immature newborn.