Brown Vaginal Discharge: Causes, Timing, and When to Seek Care

Brown Discharge: Differential Diagnosis

Brown discharge = old blood (oxidized hemoglobin) mixed with cervical/vaginal secretions. Timing and context determine significance.

Common Benign Causes

• Menstrual tail/onset: Beginning or end of period.
• Ovulation spotting: Mid-cycle, 1-2 days, mild cramping.
• Hormonal contraception: Breakthrough bleeding (pills, patch, ring, implant, IUD) – common first 3-6 months.
• Perimenopause: Irregular shedding, anovulatory cycles.
• Postcoital: Cervical ectropion, polyp, atrophy.

Pregnancy-Related

• Implantation bleeding: 6-12 DPO, scant, short.
• Threatened miscarriage: Bleeding + closed cervix + viable fetus.
• Ectopic pregnancy: Bleeding + pain + hCG discordance – emergency.
• Molar pregnancy: Dark discharge + high hCG + ultrasound findings.

Pathologic Causes

• Infection: BV, trichomonas, cervicitis (GC/CT), PID – often + odor, irritation, dysuria.
• Cervical/endometrial polyp: Intermenstrual/postcoital spotting.
• Endometrial hyperplasia/cancer: Postmenopausal bleeding, abnormal uterine bleeding >45.
• IUD complication: Expulsion, embedment.

When to See a Clinician

• Postmenopausal any bleeding.
• Persistent intermenstrual bleeding (>3 cycles).
• Associated: pelvic pain, dyspareunia, fever, malodor, heavy flow.
• Pregnancy possibility + bleeding/pain.
• New discharge after new partner or unprotected sex.

Evaluation

• Speculum exam, cervical inspection.
• STI testing (NAAT for GC/CT, trichomonas, BV panel).
• hCG if reproductive age.
• Ultrasound (endometrial thickness, structural).
• Endometrial biopsy if indicated (age >45, risk factors).
• Pap/HPV co-testing per guidelines.