The relation of maternal blood group to pre-eclampsia has not been ade
quately studied in previous research. To investigate this relation, we
conducted a case-control study of primigravidae. Data on 204 consecut
ive severely pre-eclamptic patients delivered pre-term and 744 control
s were analysed using multivariate methods. After adjustment for the c
onfounding effects of maternal age, social class, origin, education, p
re-pregnancy weight and body mass index, and weight gain in pregnancy,
we found an increased risk of pre-eclampsia for mothers with blood ty
pe AB (adjusted odds ratio = 3.07; 95% confidence interval 1.48-6.36).
With respect to blood group O, A, B and Rh type, no statistically sig
nificant correlation with severe pre-eclampsia was found. Although the
se results should be considered with caution, they support the hypothe
sis of a linkage mechanism involving blood group in the inheritance of
susceptibility to pre-eclampsia.