Chlamydial serologic characteristics among intrauterine contraceptive device users: Does copper inhibit chlamydial infection in the female genital tract?
Mehanna, M.T.; Rizk, M.A.; Ramadan, M.; Schachter, J.
American Journal of Obstetrics and Gynecology 171(3): 691-693
ISSN/ISBN: 0002-9378 PMID: 8092216 DOI: 10.1016/0002-9378(94)90083-3
In Alexandria, Egypt, clinicians compared data on 54 women who were either current or prior IUD users with data on 60 pregnant women who had never used any contraception to examine the association between IUD use and the level of antichlamydia antibodies. The IUD users had a history of ectopic pregnancy (29), intact intrauterine pregnancy (22), nontubal-factor infertility (2), and tubal factor infertility (1). The cases and controls had essentially the same geometric mean serum antibody titers for Chlamydia trachomatis (10.47 vs. 6.17). Yet, women who used copper-releasing IUDs had a lower geometric mean titer than did those who used the Lippes Loop IUD, but the difference was only significant for IUD only users and IUD users with a history of ectopic pregnancy. Specifically, among women who had used a copper IUD, the geometric mean serum antibody titers for those who only used 1 type of IUD, had used an IUD just for contraception, and those who had a history of ectopic pregnancy were 4, 5.9, and 3.8, respectively, while they were 24, 25.1 and 25.1, respectively, for their Lippes Loop counterparts (p 0.05). Among IUD users who had had an intrauterine pregnancy, the titer for women using a copper IUD was 5 compared to 14.8 for those using a Lippes Loop. When the researchers used a serum titer of 1:64 as a cutoff point for the 2 subgroups of IUD users, the Lippes Loop group had a higher proportion with titers above 1:64 than did the copper IUD group (47.6% vs. 9.09%; odds ratio [OR] = 9.09). Further, a higher proportion of Lippes Loop users had a titer greater than 1:128 than did copper IUD users (OR = 10.5). These results suggest that copper either inhibits the biologic effect of C. trachomatis or suppresses the immune response to chlamydia. Based on these findings and those of previous studies, the researchers believe the former is the most likely explanation.