The incidence of spontaneous abortion in mothers with blood group O compared with other blood types

Although ABO incompatibility between mother and fetus has long been suspected as cause of spontaneous abortion in man, its precise contribution has not been completely resolved. In spite of reports in which the incompatible mating was recognized to be a cause of habitual abortion, and which eventually results in infertility or a reduction in the number of living children compared with the number in compatible matings, such effects were not observed in other studies. The aim of this review article was to show some evidence of relationship between ABO incompatibility and spontaneous abortion.