Association between maternal heterozygosity for five blood groups and reproductive success
Christoph, C.G.; Thumala, M.I.; Nazer, J.; Armanet, L.; Cifuentes, L.
Revista Medica de Chile 126(1): 27-31
1998
ISSN/ISBN: 0034-9887 PMID: 9629751 Document Number: 492935
In man, blood groups are polymorphic genetic systems. Maternal fetal incompatibility phenomena should lead to an elimination rather than a maintenance of these polymorphisms. A possible mechanism that could explain the persistence of these polymorphisms in natural populations is a selective reproductive advantage of heterozygous individuals. To explore the relationship between maternal heterozygosity for five blood groups and some obstetrical variables related to gestational success. Using a case control design, to every mother giving birth to a malformed child a consecutive mother, whose offspring was normal, was assigned as control. All women were typified for ABO, Rh, Kidd, MNSs and Duffy blood groups. Two hundred two women were studied. There was only one stillbirth, born from a heterozygous mother for all analyzed loci. Mothers that were heterozygous or homozygous for all loci had a higher frequency of malformed children. Women homozygous for all loci had a higher frequency of living offspring than the rest of the sample. Heterozygous mothers for these genetic systems have a reproductive disadvantage.