Gender ratio distortion in abortuses and live births from patients with recurrent spontaneous abortion.

PROBLEM: Gender ratio of live birth in humans is approximately 1.05 and males are born a slightly more, while gender ratio of fertilization should be 1.00, suggesting that female fetus might be more sensitive to abortion than male fetus during pregnancy.

METHOD OF STUDY: We examined karyotype of abortuses from patients with recurrent spontaneous abortion (RSA), who had at least one live birth before or after the treatment of RSA.

RESULTS: Chromosomal abnormality was not frequent (14.6%) in the abortuses from the RSA patients. Among abortuses without chromosomal abnormality, male karyotype was rare (9.2%), and this gender ratio distortion was more prominent in RSA cases not carrying autoantibodies (3.5%) than that in the RSA cases carrying autoantibodies (26.3%), with statistical significance (P = 0.009).

CONCLUSION: These observations suggested that the aborted fetuses from RSA of unknown etiology, i.e. no chromosomal abnormality and no autoantibody, were preferentially female.