The study examined the relationship between the use of oral pre-exposure prophylaxis (PrEP) and the risk of bacterial sexually transmitted infections (STIs) in African women at increased risk of HIV. A prospective cohort study in Kenyan clinics enrolled 650 sexually active HIV-negative women aged 15 years and older who were followed for 12 months from June 2021 to February 2024. At the start of the study, 60% of the women started PrEP, and another 14.6% started it during follow-up. During follow-up, an STI occurred in 19.1% of women, with the risk being lower in consistent PrEP users (6.0%) compared to non-PrEP users (12.7%), although the difference was not statistically significant. Chlamydia accounted for 87.7% of all STI diagnoses. Four HIV infections occurred during follow-up, three of which occurred in women who discontinued PrEP. The study concluded that PrEP use was not associated with an increased risk of STIs and that HIV incidence was low, confirming the effectiveness of PrEP in this population.