Evaluating fetomaternal hemorrhage by alphafetoprotein and Kleihauer following therapeutic abortions.

In a survey of 75 patients at 6-11 weeks gestation, fetomaternal hemorrhage (FMH) was detected by significant rises (greater than 2 S.D.) in maternal alphafetoprotein (AFP) levels in 57% of patients, while increased fetal cells were detected by the Kleihauer test in 24% of patients. With increasing gestation, FMH was detected more readily by both tests; however, in evaluating FMH at less than 10 weeks gestation. AFP was found to be a more sensitive and reliable marker than the Kleihauer test. We suggest that there is a gray zone for the Kleihauer test in early gestation, when erythroblasts containing embryonic hemoglobins are gradually replaced in the fetal circulation by erythrocytes containing fetal hemoglobin.