Rapid assessment of sexually transmitted diseases in a sentinel population in Thailand: prevalence of chlamydial infection, gonorrhoea, and syphilis among pregnant women - 1996

Objective: To determine the prevalence of sexually transmitted diseases (STDs) among pregnant women in Thailand, where case reporting suggests a marked decrease in STDs following a campaign promoting condom use during commercial sex. Design: Cross sectional study of women at their first visit to the study hospitals' antenatal clinics in Chiang Rai (n=500) and Bangkok (n=521). Methods: First catch urine specimens were tested for Chlamydia trachomatis and Neisseria gonorrhoeae using the Amplicor CT/NG polymerase chain reaction assay. Syphilis and HIV serological testing were performed in the study hospitals' laboratories. Results: The prevalence of chlamydial infection was 5.7%, gonorrhoea 0.2%, and syphilis 0.5% (all VDRL or RPR titres were a less than or equal to 1:4). The prevalence of HIV infection was 7.1% in Chiang Rai and 2.9% in Bangkok. In a multivariate logistic regression analysis, chlamydial infection was associated with younger age and with higher gestational age at first antenatal clinic visit, but was not associated with marital status, gravidity, city of enrolment, or HIV infection status. Conclusions: There was a low prevalence of gonorrhoea and syphilis among these pregnant women in Thailand. Chlamydial infection was detected at a higher prevalence, especially among younger women and women registering later for antenatal care. Testing of pregnant women using easily collected urine specimens and a sensitive nucleic acid amplification assay is a feasible method of rapidly assessing chlamydial and gonococcal prevalence.