• Autoantibody;
  • chromosomal abnormality;
  • karyotype

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.