Screening for fetal malformations using ultrasound and measurements of α-fetoprotein in maternal serum

Abstract

Fetal ultrasound combined with semiquantitative measurements of α-fetoprotein in maternal serum was used for early detection of neural tube defects and omphalocele in 10147 pregnancies. The accurate assessment of gestational age, obtained by ultrasound, facilitated evaluation of α-fetoprotein concentrations in selecting cases for amniocentesis. The advantage of screening with two independent methods is suggested by the finding that eight out of 10 cases with malformations (spina bifida, encephalocele, anencephalus, omphalocele) were detected when both methods were used. Screening by routine ultrasound alone detected only four malformations and by measurement of α-fetoprotein alone only seven. The results suggest that, in a low risk population, ultrasound should be combined with the measurement of α-fetoprotein in screening for neural tube defects. Measurement of α-fetoprotein is indispensable in detection of the small neural tube defects, where the fetus would survive with severe sequelae. The semiquantitative analysis of α-fetoprotein that may be used in combination with ultrasound examination is of negligible cost.