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Sexually Transmitted Infections in Women

Sexually transmitted infections (STIs) intersect daily urogynecologic and pelvic-reconstructive practice. Cervicitis presents as discharge or postcoital bleeding workups, untreated chlamydia and gonorrhea drive pelvic inflammatory disease and tubal-factor infertility, and active infection alters the risk profile of pelvic-floor and continence surgery. STIs in women encompass a broad range of pathogens — chlamydia, gonorrhea, syphilis, trichomoniasis, genital herpes, HPV, and Mycoplasma genitalium — with distinct screening, diagnostic, treatment, and prevention considerations. Approximately 1 in 5 U.S. adults had an STI in 2018, but subsequent trends differ by infection; CDC provisional 2024 data show declining reported adult chlamydia, gonorrhea and primary/secondary syphilis, with congenital syphilis still increasing.[1][31]

Screening Recommendations​

The USPSTF and CDC recommend annual screening for chlamydia and gonorrhea in all sexually active women ≤24 years and in older women with risk factors (new or multiple partners, partner with STI, inconsistent condom use).[2][3] Key additional screening points:

  • Syphilis. CDC geographic screening guidance offers testing to sexually active people aged 15–44 in counties where primary/secondary syphilis among women aged 15–44 exceeds 4.6 per 100,000; assess individual risk in other settings. ACOG 2024, reaffirmed 2025, recommends screening every pregnant patient at the first prenatal visit, in the third trimester and at birth.[4][5][32][33]
  • HIV. Universal screening at least once for all adults; annual screening for those at increased risk.[7]
  • Hepatitis B and C. At least once for all adults; hepatitis C screening in all pregnant patients.[7]
  • Trichomoniasis. Consider testing asymptomatic women at high risk or in high-prevalence settings; annual screening recommended for women with HIV.[8][9]
  • Extragenital screening. Pharyngeal and rectal NAAT testing should be considered in women based on sexual practices and shared decision-making, as urogenital-only testing misses a substantial proportion of infections.[3]

Diagnosis​

Nucleic acid amplification tests (NAATs) are the preferred diagnostic method for chlamydia, gonorrhea, trichomoniasis, and M. genitalium, with sensitivities of 86–100% and specificities of 97–100%.[1] Vaginal specimens (clinician- or self-collected) are preferred for women.[10]

  • Syphilis relies on serologic testing using a sequential algorithm (treponemal followed by nontreponemal, or vice versa). Early infection can be seronegative; compatible lesions or exposure require clinical assessment, repeat testing and treatment when indicated rather than reassurance from an early negative result.[4][1]
  • Genital herpes. Use lesion NAAT/PCR when lesions are present. Reserve type-specific serology for appropriate indications; confirm low-positive HSV-2 immunoassay results with a second method. Routine serologic screening of asymptomatic patients is not recommended.[11][12]
  • M. genitalium. FDA-cleared NAATs are available; test women with recurrent cervicitis and consider testing in PID; do not routinely screen asymptomatic patients.[1][13]

Treatment​

The 2021 CDC STI Treatment Guidelines introduced several key updates. The table summarizes uncomplicated infection regimens in nonpregnant adults unless stated. Pregnancy, PID, neurologic/ocular syphilis, disseminated infection and treatment failure require their specific pathways.[6]

InfectionFirst-line RegimenNotes
ChlamydiaDoxycycline 100 mg PO BID × 7 dNonpregnant patients; pregnancy regimen below
GonorrheaCeftriaxone 500 mg IM × 1 (1 g if ≥150 kg)Treat chlamydia if not excluded; use pregnancy-appropriate therapy
Early syphilisBenzathine penicillin G 2.4 million U IM × 1Penicillin only therapy in pregnancy; desensitize if allergic
Late latent syphilis or unknown durationBenzathine penicillin G 2.4 million U IM weekly × 3
Trichomoniasis (women)Metronidazole 500 mg PO BID × 7 d7-day regimen preferred in women; comparable randomized evidence in men is lacking
Genital herpesAcyclovir, valacyclovir, or famciclovirSuppression reduces frequent HSV-2 recurrences by 70–80%; transmission benefit is regimen/population specific
M. genitalium (macrolide-sensitive)Doxycycline 100 mg BID × 7 d → azithromycin 1 g once, then 500 mg daily × 3 dResistance-guided; not azithromycin 1 g alone
M. genitalium (macrolide-resistant / unknown)Doxycycline 100 mg BID × 7 d → moxifloxacin 400 mg daily × 7 dMacrolide resistance >50% in many regions
Mild-to-moderate PID, outpatientCeftriaxone 500 mg IM + doxycycline 100 mg BID × 14 d + metronidazole 500 mg BID × 14 dMetronidazole now routinely included

December 2025 FDA update: oral zoliflodacin (Nuzolvence) and gepotidacin (Blujepa) now have uncomplicated urogenital gonorrhea indications; this does not establish treatment for pharyngeal gonorrhea, PID or disseminated disease. Blujepa's gonorrhea indication is limited to patients with few or no alternatives. Eligibility, pregnancy/reproductive precautions and interactions differ; consult their current labels rather than substituting these for ceftriaxone automatically.[34]

Key treatment highlights:

  • Chlamydia. Doxycycline 100 mg twice daily for 7 days is now preferred over azithromycin, based on superior efficacy particularly at rectal sites.[9][7]
  • Gonorrhea. Ceftriaxone 500 mg IM single dose (1,000 mg if ≥150 kg); add antichlamydial treatment when chlamydia has not been excluded (doxycycline for nonpregnant patients; pregnancy-specific regimen below).[9][8]
  • Syphilis. Benzathine penicillin G 2.4 million units IM — single dose for early syphilis, weekly × 3 for late latent. Penicillin is the only recommended therapy in pregnancy; desensitization is required for penicillin-allergic pregnant patients.[4][1]
  • Trichomoniasis in women. Metronidazole 500 mg twice daily for 7 days (the 7-day regimen is superior to a single 2 g dose in women; randomized comparisons of these regimens in men are lacking).[9][8]
  • Genital herpes. Acyclovir, valacyclovir, or famciclovir for episodic and suppressive therapy. Suppression reduces frequent HSV-2 recurrences by 70–80%; daily valacyclovir reduces transmission in studied discordant heterosexual couples. Do not assume equal transmission evidence for every agent, HSV type or asymptomatic seropositive population.[11]
  • M. genitalium. Resistance-guided sequential therapy — doxycycline 100 mg twice daily for 7 days, followed by azithromycin 1 g once then 500 mg daily for 3 days (if macrolide-sensitive) or moxifloxacin 400 mg daily for 7 days (if macrolide-resistant or unknown). For M. genitalium-associated PID, moxifloxacin is given for 14 days; standard PID regimens do not reliably eradicate it. Seek specialist guidance in pregnancy or when resistance/contraindications limit options.[1][6]
  • PID. Ceftriaxone 500 mg IM + doxycycline 100 mg twice daily for 14 days + metronidazole 500 mg twice daily for 14 days for eligible outpatients. Hospital assessment is required for pregnancy, tubo-ovarian abscess, severe illness, inability to tolerate therapy or failure to improve within 72 hours.[9][14]

Retest treated women with chlamydia, gonorrhea or trichomoniasis at 3 months. This differs from test of cure: obtain chlamydia NAAT approximately 4 weeks after treatment in pregnancy, and test of cure 7–14 days after treatment for pharyngeal gonorrhea. Ensure partner evaluation/treatment and abstinence until the applicable regimen and interval are completed.[6][7]

Complications in Women​

Untreated STIs carry significant reproductive consequences. The numerical estimates below come from historical cohorts/reviews and vary with population, ascertainment and treatment; they are not individualized prognoses:

  • Pelvic inflammatory disease (PID). Develops in approximately 2–10% of women with untreated chlamydia within weeks to a year. C. trachomatis is the most common identified pathogen (~23% of PID cases).[15][14]
  • Infertility. Reported in 8% after one PID episode, 18% after two, and 38% after three. Most women with tubal factor infertility have no known history of PID but are seropositive for C. trachomatis.[15][16]
  • Ectopic pregnancy. Nearly 10% of first pregnancies after PID are ectopic.[15]
  • Chronic pelvic pain. Reported 3× more frequently in women with a history of PID (18% vs. 5%).[15]
  • Adverse pregnancy outcomes. Syphilis in pregnancy can cause stillbirth in up to 40% of exposed fetuses; congenital syphilis cases increased 106% from 2019 to 2023. Chlamydia and gonorrhea are associated with preterm delivery, PPROM, and neonatal ophthalmia.[4][17]
  • Repeat chlamydial infections are associated with increased risk of PID and reproductive sequelae.[18][19]

STIs During Pregnancy: Screening, Treatment, and Complications​

InfectionScreening ScheduleTreatment in PregnancyMaternal / Fetal Complications
SyphilisFirst prenatal visit, ~28 wk, deliveryBenzathine penicillin G (desensitize if allergic)Stillbirth up to 40%; congenital syphilis ↑106% (2019–2023)
HIVFirst prenatal visit (universal)Antiretroviral therapyVertical transmission
Hepatitis BFirst prenatal visit (universal)per HBV protocols; neonatal HBIG + vaccineVertical transmission
Hepatitis CAll pregnant patientsPostpartum DAA therapyVertical transmission
ChlamydiaRisk-based at first prenatal visitAzithromycin 1 g orally once; test of cure at ~4 wkPreterm delivery, PPROM, neonatal ophthalmia
GonorrheaRisk-based at first prenatal visitCeftriaxonePreterm delivery, neonatal ophthalmia
TrichomoniasisIf symptomatic or high-risk / HIV+MetronidazolePPROM, preterm delivery

Prevention​

HPV Vaccination​

The 9-valent HPV vaccine (Gardasil 9) targets HPV types responsible for ~90% of cervical cancers and is the only HPV vaccine available in the U.S.[20][21]

  • Routine vaccination. CDC recommends age 11–12, with initiation permitted at 9. Catch up through 26 if incomplete: two doses when started before 15; three doses when started at 15 or older, and for immunocompromised patients regardless of younger starting age.[35][20][22]
  • Ages 27–45. Shared clinical decision-making for previously unvaccinated individuals.[23][24]
  • Population-level impact. Cervical cancer incidence has declined ~69% in vaccinated females aged 20–24; CIN3 declined 34% in ages 15–19.[22]
  • Screening recommendations apply regardless of vaccination status.[25]

Doxycycline Post-Exposure Prophylaxis (Doxy-PEP)​

Doxy-PEP (200 mg within 72 hours of condomless sex) has demonstrated ~80% reductions in chlamydia and syphilis and ~50% reduction in gonorrhea among MSM and transgender women.[26][27] However, the CDC currently recommends doxy-PEP only for MSM and transgender women with a bacterial STI in the past 12 months — CDC makes no recommendation for cisgender women because evidence is insufficient. The Kenyan randomized trial found no significant benefit; doxycycline was detected in only 29% of tested hair samples. Low adherence is a possible explanation, not proof that an effective regimen has been established for women. Maximum dosing is 200 mg per 24 hours.[27][28]

Other Prevention Strategies​

  • Consistent condom use provides moderate protection (HR 0.70 for HSV-2 transmission).[12]
  • Expedited partner therapy is permitted in most states to limit STI spread.[7]
  • Behavioral counseling is recommended for all adolescents and adults at increased STI risk.[14]

Special Populations​

  • Pregnancy. Universal screening for HIV, syphilis, and hepatitis B; screen for hepatitis C during each pregnancy; chlamydia/gonorrhea screening depends on age and risk. Syphilis screening should occur at least 3 times during pregnancy.[7][5]
  • Women with HIV. Screen for gonorrhea, chlamydia, syphilis, and trichomoniasis at entry to care and at least annually; every 3–6 months for those with multiple partners.[8]
  • Adolescents. At highest risk for chlamydia and gonorrhea; provide confidential, developmentally appropriate care under applicable local consent rules.[7]
  • Women who have sex with women. Do not assume low risk from identity or partner gender alone; screen according to anatomy, exposures and applicable age/risk recommendations.[7]

Antimicrobial Resistance Concerns​

Antimicrobial resistance is an escalating threat, particularly for gonorrhea (most strains remain ceftriaxone-sensitive, but resistance monitoring is critical) and M. genitalium (macrolide resistance >50% in many regions, with increasing fluoroquinolone resistance).[8][29][30] All gonorrhea treatment failures should have culture with antimicrobial susceptibility testing.[8]

See Also​

References​

1. Tuddenham S, Hamill MM, Ghanem KG. "Diagnosis and Treatment of Sexually Transmitted Infections: A Review." JAMA. 2022;327(2):161-172. doi:10.1001/jama.2021.23487

2. US Preventive Services Task Force, Davidson KW, Barry MJ, et al. "Screening for Chlamydia and Gonorrhea: US Preventive Services Task Force Recommendation Statement." JAMA. 2021;326(10):949-956. doi:10.1001/jama.2021.14081

3. Yonke N, Aragón M, Phillips JK. "Chlamydial and Gonococcal Infections: Screening, Diagnosis, and Treatment." Am Fam Physician. 2022;105(4):388-396.

4. Chevalier FJ, Bacon O, Johnson KA, Cohen SE. "Syphilis." JAMA. 2025. doi:10.1001/jama.2025.17362

5. US Preventive Services Task Force, Silverstein M, Wong JB, et al. "Screening for Syphilis Infection During Pregnancy: US Preventive Services Task Force Reaffirmation Recommendation Statement." JAMA. 2025;333(22):2006-2012. doi:10.1001/jama.2025.5009

6. Workowski KA, Bachmann LH, Chan PA, et al. "Sexually Transmitted Infections Treatment Guidelines, 2021." MMWR Recomm Rep. 2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1

7. Klein DA, Valerio CR, Cofield ZN. "Sexually Transmitted Infections: Updated Guideline From the CDC." Am Fam Physician. 2022;105(5):553-557.

8. Horberg M, Thompson M, Agwu A, et al. "Primary Care Guidance for Providers of Care for Persons With Human Immunodeficiency Virus: 2024 Update by the HIV Medicine Association of the Infectious Diseases Society of America." Clin Infect Dis. 2024. doi:10.1093/cid/ciae479

9. Dalby J, Stoner BP. "Sexually Transmitted Infections: Updates From the 2021 CDC Guidelines." Am Fam Physician. 2022;105(5):514-520.

10. Miller JM, Binnicker MJ, Campbell S, et al. "Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2024 Update by the IDSA and ASM." Clin Infect Dis. 2024. doi:10.1093/cid/ciae104

11. Gnann JW, Whitley RJ. "Genital Herpes." N Engl J Med. 2016;375(7):666-674. doi:10.1056/NEJMcp1603178

12. Plunkett M, Neville CT, Chang JG. "Genital Herpes: Rapid Evidence Review." Am Fam Physician. 2024;110(5):487-492.

13. Wood GE, Bradshaw CS, Manhart LE. "Update in Epidemiology and Management of Mycoplasma genitalium Infections." Infect Dis Clin North Am. 2023;37(2):311-333. doi:10.1016/j.idc.2023.02.009

14. Curry A, Williams T, Penny ML. "Pelvic Inflammatory Disease: Diagnosis, Management, and Prevention." Am Fam Physician. 2019;100(6):357-364.

15. Wiesenfeld HC. "Screening for Chlamydia trachomatis Infections in Women." N Engl J Med. 2017;376(8):765-773. doi:10.1056/NEJMcp1412935

16. Tsevat DG, Wiesenfeld HC, Parks C, Peipert JF. "Sexually Transmitted Diseases and Infertility." Am J Obstet Gynecol. 2017;216(1):1-9. doi:10.1016/j.ajog.2016.08.008

17. Reese PC. "STIs During Pregnancy." Am Fam Physician. 2024;109(1):10-12.

18. den Heijer CDJ, Hoebe CJPA, Driessen JHM, et al. "Chlamydia trachomatis and the Risk of Pelvic Inflammatory Disease, Ectopic Pregnancy, and Female Infertility: A Retrospective Cohort Study Among Primary Care Patients." Clin Infect Dis. 2019;69(9):1517-1525. doi:10.1093/cid/ciz429

19. Haggerty CL, Gottlieb SL, Taylor BD, et al. "Risk of Sequelae After Chlamydia trachomatis Genital Infection in Women." J Infect Dis. 2010;201 Suppl 2:S134-155. doi:10.1086/652395

20. Markowitz LE, Unger ER. "Human Papillomavirus Vaccination." N Engl J Med. 2023;388(19):1790-1798. doi:10.1056/NEJMcp2108502

21. DeSieghardt A, Ding L, Ermel A, et al. "Population-Level Effectiveness and Herd Protection 17 Years After HPV Vaccine Introduction." JAMA Pediatr. 2025;179(12):1326-1334. doi:10.1001/jamapediatrics.2025.3568

22. American Cancer Society. Cancer Prevention and Early Detection Facts & Figures. American Cancer Society; 2025.

23. ACOG Committee Opinion No. 809. "Human Papillomavirus Vaccination." Obstet Gynecol. 2020;136(2):e15-e21. doi:10.1097/AOG.0000000000004000

24. Meites E, Szilagyi PG, Chesson HW, et al. "Human Papillomavirus Vaccination for Adults: Updated Recommendations of the Advisory Committee on Immunization Practices." MMWR Morb Mortal Wkly Rep. 2019;68(32):698-702. doi:10.15585/mmwr.mm6832a3

25. Perkins RB, Wentzensen N, Guido RS, Schiffman M. "Cervical Cancer Screening: A Review." JAMA. 2023;330(6):547-558. doi:10.1001/jama.2023.13174

26. Peters RPH, Grinsztejn B, Celum C, et al. "Innovations in the Biomedical Prevention, Diagnosis, and Service Delivery of HIV and Other Sexually Transmitted Infections." Lancet. 2025;406(10515):2133-2151. doi:10.1016/S0140-6736(25)00983-3

27. Bachmann LH, Barbee LA, Chan P, et al. "CDC Clinical Guidelines on the Use of Doxycycline Postexposure Prophylaxis for Bacterial Sexually Transmitted Infection Prevention, United States, 2024." MMWR Recomm Rep. 2024;73(2):1-8. doi:10.15585/mmwr.rr7302a1

28. Stewart J, Oware K, Donnell D, et al. "Doxycycline Prophylaxis to Prevent Sexually Transmitted Infections in Women." N Engl J Med. 2023;389(25):2331-2340. doi:10.1056/NEJMoa2304007

29. Williamson DA, Chen MY. "Emerging and Reemerging Sexually Transmitted Infections." N Engl J Med. 2020;382(21):2023-2032. doi:10.1056/NEJMra1907194

30. Machalek DA, Tao Y, Shilling H, et al. "Prevalence of Mutations Associated With Resistance to Macrolides and Fluoroquinolones in Mycoplasma genitalium: A Systematic Review and Meta-Analysis." Lancet Infect Dis. 2020;20(11):1302-1314. doi:10.1016/S1473-3099(20)30154-7

31. CDC. Sexually Transmitted Infections Surveillance, 2024 (Provisional). National surveillance.

32. CDC. County-level Syphilis Data. November 2024. Screening guidance.

33. ACOG. Screening for Syphilis in Pregnancy. April 2024; reaffirmed October 2025. Practice advisory.

34. FDA. FDA Approves Two Oral Therapies to Treat Gonorrhea. December 12, 2025. FDA announcement.

35. CDC. HPV Vaccine Recommendations. Age and dose schedules.