Morphology of rapidly adhering amniotic-fluid cells as an aid to the diagnosis of neural-tube defects.

In 20 amniotic-fluid samples taken in the second trimester from pregnancies in which the fetus had a neural-tube defect, the proportion of the total viable cell which adhered to glass surfaces after 20 hours in culture ranged from 9 to 100%. In 92 normal amniotic fluids this proportion was less than 6%. Furthermore, the morphology of the rapidly adhering cells was characteristic in spina bifida (8 cases) and anencephaly (12 cases) and distinct from the epithelioid-like cell seen in normal amniotic fluids, including many which were grossly blood-stained. A sample of amniotic fluid from fetal exomphalos and one from a pregnancy in which the placenta had been repeatedly traversed during amniocentesis had proportions of adherent cells in the pathological range, but the morphologies were very different from those seen in neural-tube defects. It is suggested that the techniques described here will be useful adjuncts to amniotic-fluid alpha-fetoprotein determination in the early diagnosis of fetal abnormality, particularly in blood-stained samples.