Universal screening for chlamydia infection in pregnancy is recommended by ACOG to prevent adverse birth outcomes. Chlamydia trachomatis (CT) is an intracellular bacteria that can lead to persistent or recurrent infection despite therapy in 7-15% of non-pregnant women. Since data in pregnancy is minimal, we sought to determine rates of persistent/recurrent CT infection in this group. We performed a retrospective cohort analysis of women with deliveries at our center between 11/2012 – 12/2017. Testing was performed with highly sensitive nucleic acid amplification (Roche and Aptima Hologic) on samples from genital swabs or urine samples collected during pregnancy. Therapy was not directly observed. An early test of cure period was defined as the first test 3-6 weeks after the initial positive test. The late CT testing period was defined as >6 weeks after the initial positive test and “any positive” was compared to “never positive” for women with >1 CT test. Descriptive characteristics with 95% confidence intervals were used to compute rates of persistent/recurrent CT infection. At our center, 77% (16,138/20946) of deliveries among 13,692 women had CT testing performed during pregnancy. Among these 16,138 deliveries, 1526 (9.5%; 95% CI 9.0-9.9%) had CT detected. Compared to women without CT, women with CT were significantly younger, more likely to be Black and to have public insurance. (Table 1) Early repeat CT testing was performed in 57% of CT cases and 11.6% (95% CI 9.4-13.7%) (99/857) were persistently positive. (Fig 1) Incident chamydia (reinfection was detected in 14% (75/525) of those with a negative early test of cure. Among pregnancies with follow up CT testing only later in pregnancy, 27% (119/446) had a subsequent positive CT test. Chlamydia infection was common among pregnant women screened at our urban center with a disproportionate impact on young women and Black women. Persistent/recurrent and incident CT rates were elevated at early and late time periods at rates that surpass those in non-pregnant women. Potential reasons for CT persistence/reinfection in this cohort include poor adherence or non-response to standard antibiotic therapy, altered host immunity in pregnancy or lack of partner therapy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)