Effect of maternal ABO blood type on birth weight and preeclampsia

Background: ABO blood group has been recognized as a risk factor for distinct disease states. The association between ABO blood group and adverse pregnancy outcomes has not been extensively studied, especially in relation to birth weight and preeclampsia (PE). The aim of the present study is to determine whether ABO blood group contributes to the adverse pregnancy outcomes including low birth weight and PE.Methods: Medical data including ABO phenotypes were collected from hospital electronic database and retrospectively reviewed. Adverse pregnancy outcomes included PE and low birth weight. Birth week was also noted for each subject.Results: 2177 charts of mothers who had given birth in our hospital were studied. Overall 605 (27.8%) women had type O blood, 1056 (48.5%) had type A blood, 369 (16.9%) had type B blood and 147 (6.8%) had type AB blood. Pregnant women with type B blood group had significantly lower birth weights compared with type O, A and AB. Birth weeks of all groups were found to be similar with no statistically significant difference. A total of 167 mothers were recorded as having PE. No association was observed between PE and ABO blood groups of study participants.Conclusions: Although maternal ABO phenotype is associated with low birth weight, no association was found between blood type and preeclampsia. We postulate that maternal/fetal immune system genes which are directly associated with ABO blood groups could affect pregnant with a resulting birth weight alterations