[Use of amniotic drop-volume determination in estimating fetal lung maturity]

The value of amniotic fluid drop-volume determination with a self-made Fetal Lung Maturity Apparatus in the analysis of fetal lung maturity is studied with 148 samples. The results were compared with those of L/S ratios, it shows that this method has a sensitivity of 95%, specificity 91% and accuracy 93%, if a falling-drop-interval of less than or equal to 85 seconds was taken as the defining point for lung maturity. The mean falling drop-interval was 89.0 +/- 12.3 seconds in the 18-30 th week pregnancy samples, 72.7 +/- 9.4 seconds in the 36-42 nd week samples and 81.4 +/- 9.9 seconds in the 31-35 th week samples. (P less than 0.001). The effects of blood and meconium on the testing were also studied. The drop-volume test is recommended as an accurate, rapid and easy method in predicting fetal lung maturity.