Prevalence of Chlamydia trachomatis Among Pregnant Women, Gynecology Clinic Attendees, and Subfertile Women in Guangdong, China: A Cross-sectional Survey.

Background Chlamydia trachomatis (CT) is a major cause of infertility and adverse birth outcomes, but its epidemiology among childbearing-age women remains unclear in China. This study investigated the prevalence of CT and associated factors among Chinese women aged 16-44 years who were either (1) pregnant, (2) attending gynecology clinics, or (3) subfertile. Methods We conducted a cross-sectional survey and recruited participants from obstetrics, gynecology, and infertility clinics in Guangdong between March and December 2019. We collected information on individuals' sociodemographic characteristics, previous medical conditions, and sexual behaviors. First-pass urine and cervical swabs were tested using nucleic acid amplification testing. We calculated the prevalence in each population and subgroup by age, education, and age at first sex. Multivariable binomial regression models were used to identify factors associated with CT. Results We recruited 881 pregnant women, 595 gynecology clinic attendees, and 254 subfertile women. The prevalence of CT was 6.7% (95% CI, 5.2%-8.5%), 8.2% (95% CI, 6.2%-10.7%), and 5.9% (95% CI, 3.5%-9.3%) for the above 3 populations, respectively. The subgroup-specific prevalence was highest among those who first had sex before age 25 years and older pregnant women (>35 years). The proportion of asymptomatic CT was 84.8%, 40.0%, and 60.0% among pregnant women, gynecology clinic attendees, and subfertile women, respectively. Age at first sex (<25 years), multipara, and ever having more than 1 partner increased the risk of CT. Conclusions Childbearing-age women in China have a high prevalence of CT. As most women with CT were asymptomatic, more optimal prevention strategies are urgently needed in China.