What Causes an Unusual Vaginal Odor? Four Common Reasons

Vaginal health is closely linked to overall reproductive and hormonal balance. A mild, natural scent is completely normal and varies throughout the menstrual cycle. However, a strong, persistent, or unusual vaginal odor may indicate an underlying issue that requires attention.

It is important to understand that odor alone does not automatically mean infection. The vaginal environment maintains a delicate balance of bacteria and pH levels. When that balance is disrupted, noticeable changes can occur.

Below are four common causes of unusual vaginal odor and what they may signify.

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1. Bacterial Vaginosis (BV)

Bacterial vaginosis is one of the most common causes of abnormal vaginal odor. It occurs when the natural balance of “good” and “bad” bacteria in the vagina becomes disrupted.

Key characteristics:

• A strong, fish-like odor (often more noticeable after intercourse)

• Thin, gray or white discharge

• Mild irritation (sometimes none at all)

BV is not strictly classified as a sexually transmitted infection, but sexual activity can influence bacterial balance. It is treatable with prescribed antibiotics.

Prompt treatment is important because untreated BV may increase the risk of other infections.

2. Yeast Infection

Unlike BV, yeast infections typically cause itching and irritation more than strong odor. However, some individuals may notice a mild change in scent.

Common symptoms include:

• Thick, white discharge (often described as cottage cheese-like)

• Intense itching

• Redness and swelling

• Burning sensation during urination

Yeast infections occur when Candida fungi overgrow, often due to antibiotics, hormonal changes, high blood sugar, or weakened immunity.

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3. Poor Hygiene or Trapped Moisture

The vaginal area contains sweat glands and is naturally moist. Prolonged moisture from:

• Tight synthetic underwear

• Excessive sweating

• Not changing tampons regularly

• Leaving wet swimsuits on for long periods

can create an environment where odor-producing bacteria thrive.

Maintaining proper hygiene involves:

• Wearing breathable cotton underwear

• Changing menstrual products regularly

• Avoiding harsh soaps or douching

• Gently washing with mild, unscented products

Importantly, excessive washing or douching can actually worsen odor by disrupting natural pH balance.

4. Sexually Transmitted Infections (STIs)

Certain sexually transmitted infections may cause changes in odor and discharge.

Examples include:

• Trichomoniasis (often associated with strong odor and frothy discharge)

• Chlamydia or gonorrhea (may cause abnormal discharge and pelvic pain)

STIs may also produce:

• Pain during intercourse

• Pelvic discomfort

• Bleeding between periods

Testing and medical treatment are essential if infection is suspected.