Strategy for screening pregnant women for chlamydial infection in a low-prevalence area.

OBJECTIVE: To assess the prevalence and risk factors for chlamydial infection in pregnant women in the Quebec City area and to propose strategies for a screening program. METHODS: From January 1990 to July 1991, pregnant women from six centers were cultured for Chlamydia trachomatis. One hundred thirty-six with positive results and 536 with negative results were included in a case-control study on risk factors for this infection. RESULTS: The prevalence of C trachomatis was 1.9% (136 of 7305). In a logistic regression analysis, young age (P < .0001, test for trend), nulliparity (odds ratio [OR] 3.3; P < .00001), and a new sexual partner in the last year (OR 3.3; P = .0012) were independently associated with infection. With screening restricted to pregnant women under age 25 or those with at least one risk factor, 81.7% of women positive for C trachomatis would have been detected, whereas only 40.6% of all women would have been cultured. CONCLUSION: In a low-prevalence area for chlamydial infection in pregnant women, pre-screening criteria could optimize the use of specific diagnostic tests.