In 45 cases of trisomy 18 and 493 control pregnancies at 10-14 weeks of ges
tation, maternal serum inhibin A. total activin A, free beta -hCG and PAPP-
A were measured. In the trisomy IS pregnancies the median values were 0.74
MoM for inhibin A, 1.23 MoM for activin A, 0.38 MoM for free beta -hCG and
0.16 MoM for PAPP-A, The degree of deviation from normal in the levels of i
nhibin and activin is small in comparison with free beta -hCG and PAPP-A an
d they are therefore unlikely to be of value in improving the sensitivity o
f 90% for a 1% false-positive rate achieved by screening with fetal nuchal
translucency and maternal serum free beta -hCG and PAPP-A. Copyright (C) 20
01 John Wiley & Sons, Ltd.