Objective: The relationship between high-titer immunoglobulin G antibodies to Chlamydia trachomatis and recurrent spontaneous abortions was evaluated.
Study design: Sera from the female partners of 258 couples with unexplained infertility, no history of chlamydial infection, and negative cervical cultures were diluted 1:128 and tested for immunoglobulin G antibodies to Chlamydia trachomatis. A subset of patients was also tested for antibodies to cytomegalovirus, cardiolipin, nuclear antigens, lactoferrin, and spermatozoa.
Results: Seven (41%) of 17 women with three abortions and 6 (60%) of 10 women with four abortions had chlamydial antibodies as opposed to 20 (13.5%) of 148 with no abortions, 6 (12.8%) of 47 with one abortion, and 4 (12.1%) of 33 with two abortions (p < 0.01). The incidence of > or = 3 spontaneous abortions was 31.8% among women with high-titer chlamydial antibodies and 7.5% among women who had seronegative results (p < 0.001). There was no relation between any of the other antibodies and > or = 3 abortions or antibodies to Chlamydia trachomatis.
Conclusion: High-titer immunoglobulin G antibody to Chlamydia trachomatis was associated with recurrent spontaneous abortions. The mechanism may involve reactivation of a latent chlamydial infection, endometrial damage from a past chlamydial infection, or an immune response to an epitope shared by a chlamydial and a fetal antigen.