BACKGROUND: Chlamydia trachomatis is a common bacterial sexually transmitted infection that can persist or recur after antibiotic treatment. Universal screening for chlamydia in pregnancy is recommended to prevent adverse birth outcomes. Single-dose oral azithromycin has been the first-line therapy for chlamydia in pregnancy since 2006. OBJECTIVE: In the setting of limited data and rising sexually transmitted infection rates in the United States, our goal was to document rates and risk factors for persistent or recurrent chlamydia after azithromycin treatment in pregnancy. STUDY DESIGN: This retrospective cohort study included pregnancies with urogenital chlamydia and follow-up testing in women who delivered at an Alabama facility between November 2012 and December 2017. Pregnancies with prescribed azithromycin therapy and repeat chlamydia testing ≥21 days later were included. Chlamydia trachomatis nucleic acid amplification testing was performed on genital swab or urine samples. Descriptive characteristics and birth outcomes were compared for categories stratified by repeat test results: persistence (+ +), recurrence (+ - +), or clearance (+ -). Logistic regression models were used to identify demographic and clinical risk factors for persistent or recurrent chlamydia in pregnancy. RESULTS: Among 810 women with 840 pregnancies with repeat chlamydia testing after azithromycin treatment, 114 (14%) had persistence and an additional 72 (9%) had recurrence later in pregnancy. The median time to repeat testing was 30 days (interquartile range, 24-49 days). Concomitant gonorrhea or syphilis in pregnancy was independently associated with persistent or recurrent chlamydia (adjusted odds ratio, 1.6; 95% confidence interval, 1.1-2.4). CONCLUSION: Persistent or recurrent chlamydia after azithromycin treatment was detected in nearly 1 in 4 pregnancies with repeat testing in our urban center, highlighting the importance of performing a test of cure and ensuring partner therapy to reduce recurrent chlamydia risk.