The factor VIII ratio in normal and pathological pregnancies.

The factor VIII ratio was measured in 102 pregnant women (43 uncomplicated pregnancies, 19 with pre-eclampsia without fetal growth retardation, 8 pre-eclampsia complicated by fetal growth retardation, 12 with only fetal growth retardation and 20 with gestational diabetes). The pathological pregnancies showed a statistically significant elevation of the factor VIII ratio compared to the normal pregnancies. The group of pre-eclampsia complicated by fetal growth retardation showed the most marked increase of the factor VIII ratio. The results are discussed in relation to the hypothesis that the elevated factor VIII ratio is mainly due to the release of factor VIII antigen by various forms of vascular stress.