RESUMO
The frequencies of HLA antigens were determined in an experimental group of women with recurrent gestational disorders mainly expressed as spontaneous abortions of unknown etiology. The estimated antigen frequencies in this group were compared with the antigen frequencies in 158 unrelated persons (79 couples with no record of secondary infertility). A significantly higher frequency of antigen HLA-A9 was found in the experimental group as compared with the controls (corrected P = 0.0015). A greater degree of HLA compatibility was found between each woman from this group and her husband, considering 45 couples, as compared with 79 control couples. These results indicate that gene(s) close to the HLA region may have an influence on the reproductive performance in humans.