The use of multivariate discriminant analysis in the antenatal detection of fetal neural tube defects.

Early second trimester amniotic fluid is classified by stepwise discriminant analysis involving the computer program BMDP77, based upon biochemical analyses for alpha-fetoprotein and eight other easily assayed variables. The outcome of about 800 pregnancies has been predicted on this basis, over 80 of which were associated with fetal neural tube defects. Classification is shown to be more reliable than using alpha-fetoprotein and gestational age alone. Although in practice this approach has now been superceded by the introduction of the analysis of acetylcholine-esterase isoenzyme activity in amniotic fluid, the results demonstrate a successful application of discriminant analysis to medical diagnosis.