Female infertility is a significant global health concern, leading to substantial financial and healthcare burdens for individuals and health systems. In sub-Saharan Africa (SSA) and Southeast Asia (SEA), limited evidence exists regarding the relationship between STIs and infertility. STIs can lead to both symptomatic and asymptomatic pelvic inflammatory disease (PID), which, if left untreated, may cause infertility, a well-documented sequence supported by causal research. To inform resource allocation and strategic investment, there is a pressing need to better understand the role of STIs in causing infertility in SSA and SEA, with the goal of guiding the design of potential cohort studies or clinical trials. This research was commissioned by the Bill & Melinda Gates Foundation's Women's Health Innovations Program Strategy Team and aims to address critical questions regarding the prevalence of infertility, and the contribution of specific pathogens including Chlamydia trachomatis, Neisseria Gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, and Treponema pallidum to PID and infertility in SSA and SEA.
Among five key STIs included in the literature review, chlamydia shows the most substantial associations with both PID and infertility, particularly tubal-factor infertility. This is supported by two randomized trials indicating that screening and treating for chlamydia can reduce the incidence of clinical PID. There is moderate-quality evidence associating gonorrhea with PID and infertility. Evidence is mixed or more limited for associations between T. vaginalis, M. genitalium, and syphilis with PID and infertility. There are difficulties in diagnosing STIs and infertility in low- and middle-income countries (LMICs) related to high testing costs, reliance on symptom-based diagnosis (rather than molecular or antibody tests), and limited access to diagnostic facilities. Another challenge in this area of work is the extensive variability in the definitions and diagnosis of PID and infertility. Many studies rely on self-reporting or medical records for diagnosis. There is a need for clearly stated and standardized criteria for future studies.
