Assessment of fetal lung maturity by free-floating particles in amniotic fluid and biparietal diameter by ultrasonography.

ABSTRACT

The accuracy of Free-floating particles (FFPs) and biparietal diameter (BPD) detected and measured by ultrasonography for assessment of fetal lung maturity were compared with the lecithin/sphingomyelin (L/S ratio) which was used as the gold standard. One hundred pregnant women in the lately third trimester who required amniocentesis for fetal lung maturity testing, from July 1998 to August 1999 at Siriraj Hospital, were included in this study. Ultrasonography was performed to evaluate the presence of FFPs in the amniotic fluid and the BPD was measured. Amniotic fluid for L/S ratio was obtained by amniocentesis. The presence of FFPs had a 58.3% specificity and a 41.7% false positive rate. A BPD value of at least 94 millimeters had 100% specificity and no false positives. When the presence of FFPs and a BPD value of at least 93 millimeters were used in combination, the test gave 100% specificity and no false positives. The presence of FFPS and a BPD value of at least 93 millimeters detected by real time ultrasonography may be used as predictive parameters to indicate fetal lung maturity.