Sexually Transmitted Infection Epidemiology in Pregnant Populations

Pregnant women experience a uniquely complex interplay of biological, social and health-system factors that influence the incidence and impact of sexually transmitted infections (STIs). Bacterial infections such as Chlamydia trachomatis and Neisseria gonorrhoeae, protozoan infestation by Trichomonas vaginalis and dysbiosis manifesting as bacterial vaginosis are highly prevalent in many low- and middle-income settings and commonly remain asymptomatic. Untreated infections in pregnancy are associated with an increased risk of miscarriage, stillbirth, preterm delivery, low birthweight, neonatal conjunctivitis, neonatal pneumonia and even vertical transmission of HIV. Standard antenatal care in many regions relies on syndromic management of STIs, which often misses asymptomatic cases and may contribute to persistent transmission and antimicrobial resistance. Emerging evidence supports targeted approaches such as point-of-care testing and immediate treatment in antenatal clinics, underpinned by mathematical modelling that projects reductions in adverse birth outcomes and vertical HIV transmission. Nevertheless, implementation is hampered by cost, logistical constraints and variable health-system capacity. Surveillance gaps, heterogeneity in prevalence across regions and the increasing burden of drug-resistant gonorrhoea further complicate efforts to optimise maternal and neonatal health. A concerted global strategy that integrates robust diagnostics, routine antenatal screening, partner services and strengthened data collection is essential to reduce the burden of curable STIs in pregnancy and to safeguard both maternal and infant outcomes.

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Sexually Transmitted Infection Epidemiology in Pregnant Populations publication trend

The graph below shows the total number of articles in sexually transmitted infection epidemiology in pregnant populations across all publications each year (not limited to Nature Index journals).

Technical terms

Chlamydia trachomatis: A bacterial pathogen that often causes asymptomatic urogenital infection and is linked to adverse pregnancy and neonatal outcomes.

Neisseria gonorrhoeae: The bacterial agent of gonorrhoea, capable of infecting the maternal genital tract and contributing to preterm birth and pelvic inflammation.

Trichomonas vaginalis: A protozoan parasite responsible for trichomoniasis, which can provoke inflammation and has been associated with low birthweight.

Bacterial vaginosis: A dysbiosis characterised by overgrowth of anaerobic bacteria in the vagina, increasing the risk of preterm delivery and other complications.

Point-of-care testing (POC): Rapid diagnostic assays performed in clinical settings that provide immediate results and facilitate same-visit treatment decisions.

Syndromic management: An approach to STI treatment based on recognition of clinical syndromes rather than laboratory confirmation, which may miss asymptomatic infections.

Vertical transmission: The passage of an infectious agent from mother to fetus or neonate during pregnancy, childbirth or breastfeeding.

References

1. Point-of-care testing and treatment of sexually transmitted and genital infections to improve birth outcomes in high-burden, low-resource settings (WANTAIM): a pragmatic cluster randomised crossover trial in Papua New Guinea. The Lancet Global Health (2024).
2. The effect of STI screening during pregnancy on vertical transmission of HIV and adverse pregnancy outcomes in South Africa: a modelling study. Journal of the International AIDS Society (2025).
3. Chlamydia trachomatis Infection in Pregnancy: The Global Challenge of Preventing Adverse Pregnancy and Infant Outcomes in Sub‐Saharan Africa and Asia. BioMed Research International (2016).