title: Selective interactions among Rh, ABO, and sex ratio of newborns.
abstract: The hypothesis that the Rh and ABO blood systems behave like the HLA system in relation to mother-conception tolerance-rejection mechanisms was tested in 25,501 mother-infant pairs. According to this hypothesis, heterozygotes carrying a paternal gene that is not present in their mothers should be better tolerated than homozygotes. Significantly more BO infants born to AO mothers. AO infants born to BO mothers, Rh(+) heterozygotes born to Rh(-) mothers, and less significantly AO infants born to OO mothers confirm the hypothesis. Fewer homozygotes occurred in Rh(-) infants born to Rh(+) mothers and in O infants born to non-O mothers. Deviations from the Hardy-Weinberg equilibrium found in the ABO system were modified by the Rh and sex of the infant. These data strongly support the hypothesis that at least two feto-maternal systems influence the destiny of pregnancies: the classical known incompatibility system which operates late in pregnancy and a new one which is based on the induction of maternal tolerance early in pregnancy: maternal tolerance seems to be better elicited by heterozygous eggs or embryos carrying a gene not present in the mother. The data also support the hypothesis that the sex ratio is influenced by feto-maternal tolerance-rejection mechanisms associated with the ABO and Rh systems.
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics* / Q000276:immunology; D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008431:Maternal-Fetal Exchange; D008957:Models, Genetic; D010641:Phenotype; D011247:Pregnancy; D012203:Rh Isoimmunization; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology; D012744:Sex Ratio
chemical_list: D000017:ABO Blood-Group System; D012204:Rh-Hr Blood-Group System