Obstetric implications of rhesus antigen distribution in Mozambican and Swedish women.

AB0 and Rhesus phenotypes were analyzed in 199 Mozambican women and the gene frequencies were calculated. The frequencies of the K and Fya antigens were also investigated. The findings were interpreted against the background of the corresponding phenotype distribution of a Swedish population. D- and Du-positive women amounted to 97.0%, which is significantly more than in Sweden (p < 0.001). Among AB0 groups it was found that blood group 0 is significantly more predominant in Mozambican than in Swedish women (p < 0.001). The reverse is true for blood group A (p < 0.001). Blood group B has a similar prevalence in Mozambican and Swedish women. The obstetric implication of the low prevalence of D-negative women is that the Rhesus alloimmunization problem may be of a much smaller magnitude than would be expected.