Serum IgG and IgA antibodies to Chlamydia in ectopic pregnancies

The possible association of Chlamydia trachomatis with ectopic pregnancies was evaluated in a case-control study, comprising 35 women with ectopic pregnancy and 294 apparently healthy women who served as controls. Chlamydia-specific IgG and IgA antibodies were determined by single serovar (L2) inclusion immunoperoxidase assay (IPA). Socio-demographic characteristics, gynecological history and contraceptive methods were also evaluated. An inverse relationship was found between the educational levels and the prevalence of IgG and IgA antibodies to chlamydia. The prevalence rate of elevated IPA IgG (titer greater than or equal to 128) and IPA IgA (titer greater than or equal to 16) specific to chlamydia was significantly higher in women with ectopic pregnancy versus controls (32% vs 8%, respectively, for IgG: odds ratio = 4.9; and 26% vs 4% for IgA: odds ratio = 7.5). Chlamydia trachomatis was not isolated in cell cultures in 10 specimens available from fallopian tubes of women with ectopic pregnancy. Only 9% of the women recall having pelvic inflammatory disease (PID) indicating that most of the infections were asymptomatic. Women who did not use IUD had a higher proportion of chlamydia-specific IgG and IgA seropositives, though not statistically significant, as compared to IUD users. This study further supports the hypothesis that subclinical infection of the tube with C. trachomatis may underlie ectopic pregnancies.