Contraceptive methods and the risk of Chlamydia trachomatis infection in young women.

To evaluate the relation between contraceptive methods and cervical Chlamydia trachomatis infection, the authors studied a population-based sample of 1,779 nonpregnant women aged 15-34 years who underwent cell culture diagnostic testing for the detection of C. trachomatis at a health maintenance organization. Barrier contraceptive method users were classified as those who reported using one of the following methods at time of testing: condom, diaphragm, cervical cap, spermicidal sponge, foam, or vaginal spermicidal suppositories. Barrier methods were associated with a reduction in the risk of chlamydial infection in women aged 25 years or older when compared with all other women in the same age category (adjusted prevalence odds ratio = 0.15, 95% confidence interval (CI) 0.04-0.66). When compared with only noncontracepting women, the adjusted prevalence odds ratio was 0.34 (95% CI 0.06-1.99). The protective effect of barrier methods was not evident in women younger than age 25 years. Oral contraceptive use was not associated with the risk of C. trachomatis infection using either referent group; the adjusted prevalence odds ratio was 0.99 (95% CI 0.57-1.73) compared with all other women, and 0.88 (95% CI 0.44-1.79) compared with noncontracepting women. These findings suggest that present patterns of use of barrier methods differ by age and afford only selective protection against cervical C. trachomatis infections.