Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae among high-risk pregnant women in Thailand: implications for antenatal screening and perinatal outcomes

BACKGROUND: Chlamydia trachomatis and Neisseria gonorrhoeae are common sexually transmitted infections linked to adverse pregnancy outcomes; however, routine antenatal screening is not performed. Pregnant women with syphilis, hepatitis B virus, or HIV are high risk, yet prevalence in this group is unclear. OBJECTIVE: To determine the prevalence of C. trachomatis and N. gonorrhoeae among high-risk pregnant women and evaluate associated maternal and neonatal outcomes. METHODS: This cross-sectional study was conducted at Siriraj Hospital, Bangkok, Thailand, from 2022 through 2025. Endocervical swabs underwent nucleic acid amplification testing for C. trachomatis and N. gonorrhoeae, and vaginal smears were examined for bacterial vaginosis. Maternal and neonatal outcomes were analyzed using logistic regression. RESULTS: Among 119 women aged of 15-42 (24.8 ± 6.3) years (syphilis alone, 62.1%; hepatitis B virus, 22.7%; HIV, 7.6%; co-infection, 7.6%), prevalence was 18.5% for C. trachomatis, 3.4% for N. gonorrhoeae, and 13.4% for bacterial vaginosis. No independent maternal risk factors were identified. C. trachomatis was significantly associated with intrapartum fever (odds ratio 3.78; P = 0.045) and neonatal intensive care unit admission (odds ratio 7.50; P = 0.043). CONCLUSIONS: C. trachomatis was highly prevalent and significantly associated with adverse outcomes, supporting targeted screening in high-risk pregnancies.