The use of the amniotic fluid lecithin/sphingomyelin (L/S) ratio, creatinine concentration and nile blue sulphate tests, individually and in combination, in the assessment of fetal lung maturity.
The lecithin-sphingomyelin (LS) ratio is a good, but not absolute, test of fetal lung maturity. A total of 373 infants was delivered within 72 hours of amniotic fluid collection for assessment of the L/S ratio. Five of 43 infants (11-6 per cent) with an L/S ratio of 2-2 or less developed the respiratory distress syndrome (RDS), whereas only one of 320 infants (0-31 per cent) with a higher L/S ratio developed RDS. The risk of RDS could be further defined by using the creatinine concentration (critical value 19 mg/1) and the Nile blue sulphate test (critical value 4 per cent) in combination with the L/S ratio. All three tests were performed in 320 pregnancies and in each instance delivery took place within 72 hours. When all three test results were low, 3 of 5 infants (60 per cent) developed RDS, whereas when all three results were high, none of 175 infants developed RDS. When one or two results were low, 2 of 140 infants (1-4 per cent) developed RDS.
D000653:Amniotic Fluid / Q000032:analysis*; D001034:Apgar Score; D001724:Birth Weight; D003404:Creatinine / Q000032:analysis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D010713:Phosphatidylcholines / Q000032:analysis*; D011247:Pregnancy; D012127:Respiratory Distress Syndrome, Newborn / Q000209:etiology; D012306:Risk; D013109:Sphingomyelins / Q000032:analysis*; D013431:Sulfates / Q000032:analysis
D010713:Phosphatidylcholines; D013109:Sphingomyelins; D013431:Sulfates; D003404:Creatinine