Sentinel surveillance of Chlamydia trachomatis infection in women terminating pregnancy

To evaluate demographic characteristics of women terminating their pregnancy for sentinel surveillance of Chlamydia trachomatis infection and to report changing prevalences of C trachomatis over time within this study population.

Screening for C trachomatis in women seeking induced abortion was introduced in 1984 at the Department of Gynecology, Regional Hospital, Trondheim, Norway. Over the study years our department has used a precoded medical record covering sociodemographic, medically relevant data, also recording outcome of the C trachomatis test. Throughout the study the Department of Microbiology applied cell culture, enzyme immunoassay, and, during the most recent years a nucleic acid test to identify C trachomatis.

Chi square test for linear trend and unconditional logistic regression.

Over the study period, women having induced abortion were characterised by being most often single and more often at younger age. The overall age-adjusted prevalence of C trachomatis declined from 9.2% in 1985 to 3.6% in 1995, the major decline occurring from 1987 to 1991, and affected all age-groups simultaneously. There was a 60% decrease in odds ratio of having a C trachomatis infection from 1985 to 1991, and the crude and the adjusted odds ratios did not differ for any year examined.

Women deciding on pregnancy termination have demographic characteristics that identify high-risk groups for C trachomatis infection. Despite these characteristics, which were relatively constant over the study period, the study population changed from being a high- to a low-prevalence population of C trachomatis.