Elevated maternal αFP due to foeto-maternal haemorrhage

Abstract

Elevated maternal serum levels of α-foetoprotein have been used as a screening procedure in the prenatal diagnosis of foetal neural tube defects where levels about the 98th percentile are indications for further testing. False positives due to multiple pregnancies, threatened abortions and incorrect gestations are well documented, however many false positives remain unexplained. In a survey of 150 women who gave birth to normal infants, 11/69 (16%) of women with anterior placentas revealed elevated maternal αFP levels associated with increased numbers of foetal cells. This suggests that foeto-maternal haemorrhage in an otherwise normal pregnancy can account for a percentage of raised αFP levels. The use of Kleihauer technique would eliminate elevated αFP levels due to foetomaternal haemorrhage that appears to be prevalent in women with anterior placentas.