EVALUATION OF THE SMALL 3RD-TRIMESTER FETUS USING THE FOAM STABILITY INDEX TEST

  • 1 January 1981
    • journal article
    • research article
    • Vol. 58  (3) , 314-318
Abstract
The diagnostic effectiveness of the lecithin:sphingomyelin (L:S) ratio was compared to that of the quantitative amniotic fluid foam stability index (FSI) test in the prenatal evaluation of pregnancies associated with fetuses appropriately grown for gestational age (AGA) and with intrauterine growth retardation (IUGR). In 27 such pregnancies both the L:S ratio assay and the FSI test were performed on amniotic fluid specimens collected within 72 h of delivery. Of the 27 low birthweight (LBW) [human] neonates studied, 15 were small for gestational age (SGA) but did not have idiopathic respiratory distress syndrome (IRDS); of 12 AGA neonates, 9 had IRDS. The 15 IUGR cases were characterized by FSI values varying from 0.47-0.55; the 12 AGA cases had values varying from 0.42-0.48. The FSI showed excellent differentiation between these 2 entities. The L:S ratio ranged from 1.1-3.4 in cases associated with IUGR and from 1.0-2.4 in AGA cases, showing a high degree of overlap. The combination of an L:S ratio of < 1.5 and a FSI value of < 0.47 consistently identified the fetus who would have IRDS.