[Prenatal determination of lung maturity from amniotic fluid--indications and new methods]

Although fetal lung maturity determination is carried out more and more rarely in the German-speaking area, a reliable information about the degree of lung maturity is still very important in the care of high-risk pregnancies. The side effects and costs of a postpartal surfactant administration can be avoided if lung maturity is proved. Indications for determination of fetal lung maturity are the threatening preterm delivery and the premature rupture of membranes before the 34th week of gestation and uncertain gestational age. Furthermore, in preeclampsia resp. in diabetes mellitus, which is difficult to control, premature delivery may be necessary. To improve lung maturity testing we introduce a new "sequence scheme" containing three lung maturity tests which are easy to carry out (in the following sequence: Amniostat-FLM ultrasensitive, counting of the lamellar bodies in amniotic fluid, surfactant/albumin ratio with TDx-FLM). The principle of this scheme is, that if any of these three tests indicates lung maturity, the sequence is terminated and no further test is performed. Only if all three tests indicated immaturity, the child was at risk for RDS. In 87 amniotic fluid samples with 7 RDS-cases, we achieved high predictive values for lung maturity (specificity 90%, sensitivity 100%, predictive value of positive test 47%, predictive value of negative test 100%). In 62% only one test was needed for lung maturity determination. It is possible to use other combinations in such a scheme (e.g. the L/S ratio). This might lead to equal or perhaps better results. An advantage of this suggested "sequence scheme" is that it can be performed in any clinic.