Prenatal screening for fetal abnormalities is an accepted part of mode
rn obstetric management. Improvements on current screening procedures
need to address increased diagnostic efficacy and earlier diagnosis. T
his study evaluates the diagnostic efficacy of PAPP-A and F beta-hCG i
n the detection of first trimester pregnancy abnormalities, including
Down syndrome (DS). Of 731 pregnant volunteers: obtained from a mature
age population undergoing chorionic villus sampling (CVS), 17 DS and
11 compromised (six numerical (excluding sex chromosome) aneuploidies,
five spontaneously failed) pregnancies were detected. Application of
an algorithm, which combines PAPP-A and F beta-hCG levels with materna
l age, detected 66.6 per cent of DS pregnancies for a five per cent fa
lse positive rate. Similarly, for a 1.2 per cent recall rate: 72.7 per
cent of compromised pregnancies were detected. This report supports t
he notion that prenatal screening at 9-12 weeks of pregnancy is achiev
able with PAPP-A and F beta-hCG quantitation. Whereas mid-gestational
screening target-led the detection of fetal abnormalities, screening e
arlier in pregnancy will detect other pregnancy-related abnormalities,
in addition to aneuploidy. (C) 1998 John Wiley & Sons, Ltd.