Understanding Brown Vaginal Discharge: Causes & When to See a Doctor

Brown discharge is typically old blood that has oxidized, turning from red to brown. It's common and often benign, but context matters.

Common Benign Causes

• Start/end of period: Slow flow allows oxidation.
• Ovulation spotting: Mid‑cycle estrogen dip → slight shedding.
• Hormonal contraception: Breakthrough bleeding on pills, patch, ring, IUD (especially first 3–6 months).
• Perimenopause: Hormonal fluctuations cause irregular shedding.
• Post‑coital: Cervical ectropion or mild trauma.
• Implantation bleeding: 6–12 days post‑ovulation; light, brief.

Potentially Concerning Causes

• Infection: BV, trichomoniasis, chlamydia, gonorrhea (often with odor, itching, pain).
• Pregnancy complications: Threatened miscarriage, ectopic pregnancy (with pain, +hCG).
• Structural: Polyps, fibroids, adenomyosis.
• Endometriosis/adenomyosis: Cyclic brown spotting + pain.
• Malignancy: Endometrial/cervical cancer (rare; post‑menopausal bleeding always evaluated).

When to See a Doctor

• Brown discharge >7 days or recurring unpredictably
• Accompanied by pain, fever, foul odor, itching
• Post‑menopausal any bleeding/spotting
• After unprotected sex with new partner (STI screen)
• Known pregnancy + brown bleeding
• Personal/family history of gynecologic cancer

What to Expect at Visit

• History, speculum exam, cervical swabs (STI, cytology).
• Transvaginal ultrasound (endometrial thickness, structural lesions).
• Endometrial biopsy if >45 yrs or risk factors.

Most brown discharge is harmless hormonal ebb‑and‑flow. Persistent or symptomatic cases deserve evaluation to rule out treatable conditions.