What is the appropriate care and treatment plan for an 18-year-old on birth control, currently menstruating, who had unprotected sex 3 days ago and is concerned about STI (Sexually Transmitted Infection) risk and potential pregnancy?

Care and Treatment Plan for 18-Year-Old with Unprotected Sex 3 Days Ago

Pregnancy Risk Assessment

Since this patient is currently menstruating and on birth control, her pregnancy risk is extremely low and emergency contraception is not indicated. 1 The presence of menstrual bleeding essentially rules out pregnancy from the encounter 3 days ago, and ongoing hormonal contraception provides continuous protection if taken correctly.

Key Considerations:

• Birth control effectiveness: If the patient has been taking her hormonal contraception consistently and correctly, she remains protected even after unprotected intercourse 1
• Current menstruation: Active menstrual bleeding confirms she is not pregnant from this encounter 1
• Emergency contraception timing: While levonorgestrel can be used up to 72 hours (3 days) after unprotected sex and ulipristal acetate up to 120 hours (5 days), neither is necessary when the patient is already menstruating and on effective contraception 2, 3

Counseling Points:

• Reinforce the importance of consistent birth control use to maintain protection 1
• Discuss backup barrier methods (condoms) for dual protection against both pregnancy and STIs 1
• Clarify that hormonal contraception does NOT protect against sexually transmitted infections 1

STI Testing Protocol

Proceed with comprehensive STI screening today, as the patient is at risk for multiple infections following unprotected sexual contact. 4, 5

Immediate Testing (Today):

• Nucleic acid amplification tests (NAAT) for gonorrhea and chlamydia from cervical specimens 1, 5
• Wet mount examination of vaginal specimen for Trichomonas vaginalis and bacterial vaginosis 1, 5
• HIV testing with appropriate pre-test counseling 1
• Syphilis serology (baseline) 1, 5
• Hepatitis B serology if vaccination status is unknown 1

Follow-Up Testing Schedule:

• Repeat testing at 2 weeks: Gonorrhea and chlamydia testing should be repeated if initial tests were negative and prophylactic treatment was not given, as infectious agents may not have reached detectable concentrations at the initial 3-day post-exposure visit 1
• Repeat HIV and syphilis testing at 12 weeks (3 months) to detect seroconversion, as antibodies may not be detectable in the early window period 1

Important Testing Caveats:

• Window period considerations: Initial negative tests do not definitively rule out infection due to incubation periods 1
• Test sensitivity: NAAT testing is preferred over culture for chlamydia and gonorrhea due to superior sensitivity 1, 5
• Site-specific testing: If there was oral or anal contact, obtain pharyngeal and rectal specimens as appropriate 1, 5

Treatment Approach

Empiric Treatment Decision:

Do NOT initiate empiric antibiotic treatment at this visit unless the patient has symptoms of mucopurulent cervicitis, pelvic inflammatory disease, or comes from a high-prevalence population. 1, 5

• Await test results if the patient is asymptomatic and likely to return for follow-up 1
• Consider empiric treatment only if: 1
  • Patient is unlikely to return for results
  • High community prevalence of gonorrhea and chlamydia
  • Clinical signs of cervicitis or pelvic inflammatory disease are present

If Empiric Treatment Is Indicated:

• Gonorrhea: Ceftriaxone 500 mg IM (or 1 g IM if body weight ≥150 kg) 5
• Chlamydia: Doxycycline 100 mg orally twice daily for 7 days (preferred over azithromycin) 1, 5

Partner Management

The patient must notify her sexual partner(s) for evaluation and treatment. 1

• Exposure interval: Any partner with sexual contact within the past 60 days should be evaluated, tested, and treated 1
• Abstinence counseling: Patient should abstain from sexual intercourse until she and her partner(s) complete treatment and are asymptomatic 1
• Health department assistance: Offer confidential partner notification services through the local health department 1

Prevention Counseling

Barrier Method Education:

Counsel the patient that consistent condom use is essential for STI prevention, even when using hormonal contraception. 1

• Latex condoms provide the best documented protection against gonorrhea, chlamydia, herpes simplex virus, hepatitis B, and HIV 1, 6, 7
• Dual method approach: Recommend using both hormonal contraception for pregnancy prevention AND condoms for STI protection 6, 8
• Female condoms are an alternative when male condoms cannot be used 1

Risk Reduction Strategies:

• Discuss limiting number of sexual partners 1
• Emphasize that hormonal contraception offers NO protection against STIs 1, 6
• Provide information about pre-exposure prophylaxis (PrEP) for HIV if at ongoing high risk 1

Follow-Up Plan

Required Follow-Up Visits:

1. 2-week visit: Repeat STI testing if initial tests negative and no prophylactic treatment given 1
2. 3-month visit: HIV and syphilis serology to detect seroconversion 1
3. Test result notification: Ensure patient receives all test results and appropriate treatment if positive 1

Red Flag Symptoms Requiring Immediate Return:

• Pelvic pain or fever (concern for pelvic inflammatory disease) 1, 5
• Abnormal vaginal discharge 1
• Dysuria or urinary symptoms 1
• Genital lesions or ulcers 5
• Missed menstrual period beyond 1 week of expected date 2

Documentation and Reporting

• Confidentiality: Maintain strict confidentiality for all STI-related care 1
• Mandatory reporting: Report positive cases of gonorrhea, chlamydia, syphilis, and HIV to local health department as required by law 1, 5
• Sexual history: Document detailed sexual history including number of partners, types of sexual contact, and contraception use 4, 5