Discussion
HIV, adverse pregnancy outcomes and infertility, infection, infections, HIV infection
STIS, INFECTION, INFECTIONS, HIV INFECTION
STIs have a major impact on both sexual and reproductive health and, in addition to their individual pathogenic effects, increase the risk of HIV, adverse pregnancy outcomes and infertility. Understanding factors that influence STI prevalence and incidence is critical for the implementation of effective management strategies to reduce the burden of these infections and associated adverse outcomes. Similar to previous studies [Younger women (18–21 years) had a higher prevalence of CT compared to older women (26–33 years), 29% vs 8% respectively. This is similar to the prevalence reported in the ECHO parent study that recorded CT prevalence of 20–28% in South African women at baseline and found that younger women were more likely to have a CT infection than older women [We measured PSA as a biomarker of semen to evaluate the relationships between recent unprotected sexual intercourse, reported condom use and STI incidence. Only 13% of individuals tested positive for PSA at baseline and, while PSA was not associated with reported condom use, it was significantly associated with reporting of recent vaginal sexual acts. We did not find any association between PSA positivity across all visits and STI incidence, and we did not observe significant differences in PSA detection between age groups, study sites or contraceptive arms. However, a study by Deese et al. [This study had several important strengths including randomization to contraceptive method, high adherence to contraceptive method and testing for STIs and other co-factors. However, limitations include the small sample size, short follow-up period, and limited power to evaluate differences between some of the STIs between the different groups. It would also be vital to study the STI incidence and prevalence rates in women living with HIV as this cohort included only seronegative women. This has importance as previous studies have reported a bidirectional relationship between HIV and STIs, with women with HIV more likely to have a STI compared to HIV-negative women [In conclusion, this study found a high prevalence and incidence of STIs, especially in young women who are also most at risk of HIV infection in South Africa [