Chlamydia trachomatis Infections Among Women Attending Prenatal Clinics: United States, 2004-2009

Background: Chlamydia screening practices, positivity, and trends from 2004 to 2009 in publicly funded prenatal clinics have not been described. Methods: A phone-based survey assessing chlamydia screening practices was conducted among a random sample of clinics providing prenatal services (prenatal, family planning, and integrated clinics: "prenatal clinics") that reported data to the Infertility Prevention Project (IPP) in 2008. Using existing IPP data, chlamydia positivity and trends were assessed among women aged 15 to 24 years seeking care in any prenatal clinic reporting >= 3 years of data to IPP from 2004 to 2009. Linear trends of the effect of year (a continuous variable) on positivity were evaluated using a correlated modeling approach with a random intercept where the unit of analysis was the individual clinic performing chlamydia tests (clinic-based analysis). Covariates included race, age, test technology, and geography. Results: Of 210 sampled clinics, 166 (79%) completed the survey. Of these, 163 (98.2%) had documented chlamydia screening criteria. Most clinics screened all women during their first trimester and reported 100% screening coverage. From 2004 to 2009, 267,416 tests among women aged 15 to 24 years were reported to IPP from eligible prenatal clinics. Overall chlamydia positivity was 8.3%. Controlling for all covariates, positivity decreased from 2004 to 2009 (odds ratio: 0.93 per year, 95% confidence interval: 0.92, 0.95, 35% decrease overall). Conclusions: The substantial burden of chlamydia among young women tested in prenatal clinics reporting data to IPP suggests the continued need for routine screening. Decreasing trends from 2004 to 2009 in the IPP prenatal population correspond to findings of overall decreasing chlamydia prevalence in the United States.