What causes bv in women

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Last updated: April 4, 2026

Quick Answer: Bacterial vaginosis (BV) is caused by an imbalance in the natural bacteria found in the vagina. When the 'good' bacteria (lactobacilli) decrease and 'bad' bacteria overgrow, it disrupts the vagina's healthy pH and leads to BV.

Key Facts

Overview

Bacterial vaginosis (BV) is a common vaginal condition that affects women of reproductive age. It's characterized by a change in the natural balance of bacteria within the vagina, leading to an overgrowth of certain types of bacteria that are normally present in smaller amounts. This imbalance can cause symptoms such as unusual vaginal discharge, odor, and sometimes discomfort.

What is the Vaginal Microbiome?

The vagina is home to a complex ecosystem of microorganisms, collectively known as the vaginal microbiome. This microbiome is typically dominated by beneficial bacteria called lactobacilli. These lactobacilli play a crucial role in maintaining vaginal health by producing lactic acid, which helps keep the vaginal pH acidic (typically between 3.8 and 4.5). An acidic environment inhibits the growth of harmful bacteria and yeasts, thus protecting against infections.

What Causes the Imbalance in BV?

Bacterial vaginosis occurs when this delicate balance is disrupted. The most common scenario involves a decrease in lactobacilli and a corresponding increase in other types of bacteria, such as Gardnerella vaginalis, Prevotella, and Mycoplasma hominis. While these bacteria are often present in a healthy vagina, their overgrowth in BV can lead to a rise in vaginal pH and the characteristic symptoms.

Factors That Can Increase the Risk of BV

While the exact triggers for this bacterial imbalance are not always clear, several factors are known to increase a woman's risk of developing BV:

Symptoms of BV

Not all women with BV experience symptoms. When symptoms do occur, they commonly include:

Why is Treating BV Important?

While BV itself is not usually dangerous, it can increase the risk of more serious health problems. Untreated BV can:

Diagnosis and Treatment

BV is typically diagnosed by a healthcare provider through a pelvic exam and by examining a sample of vaginal discharge under a microscope or performing a vaginal pH test. Treatment usually involves antibiotics, either taken orally or inserted vaginally as a gel or cream. It is crucial to complete the full course of antibiotics as prescribed, even if symptoms improve sooner.

Prevention

While not all cases of BV can be prevented, certain practices can help maintain a healthy vaginal balance:

If you suspect you have BV, it's important to consult a healthcare provider for proper diagnosis and treatment.

Sources

  1. Bacterial vaginosis - NHSfair-use
  2. Bacterial vaginosis - Symptoms and causes - Mayo Clinicfair-use
  3. Bacterial Vaginosis - CDCfair-use

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