Amniotic fluid levels of fibrin(ogen) degradation fragment E and alpha-fetoprotein in normal pregnancy and with fetal neural tube defect.

Amniotic fluid levels of alpha-fetoprotein (AFP) and fibrin(ogen) degradation fragment E (FgE) were measured in 214 normal subjects and 27 pregnancies associated with an abnormal fetus (open neural tube defect or exomphalos). AFP levels showed no overlap between the normal and abnormal groups, thus confirming the reliability of the AFP assay in the detection of these abnormalities. FgE levels however showed considerable overlap and could not be used as a diagnostic parameter. Agarose gel chromatography of the amniotic fluid revealed the presence of large molecular weight FgE related antigen in open neural tube defect suggesting that leakage of proteins from exposed capillaries is responsible for the elevation of amniotic fluid protein levels.