Bacterial Vaginosis: Symptoms, Causes & Treatment

Updated in April 2022

Bacterial vaginosis is a vaginal infection that occurs when there is an imbalance of naturally-occurring vaginal bacteria. This causes a change in vaginal pH, which promotes the growth of other, more harmful bacteria, like Gardnerella sp. 

This infection is associated with symptoms like intense itching, pain with urination, foul odor, and a thick white, yellow or gray discharge.

Although it can cause discomfort, bacterial vaginosis treatment is relatively easy and is usually done with antibiotics. It is important to see your doctor for assessment and to initiate treatment promptly. 

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Common symptoms 

Most cases of bacterial vaginosis, or BV, do not present with any signs or symptoms. It is often only diagnosed during a vaginal assessment or routine swab. 

Symptoms of infection are often noted following sex or after a period. The main symptoms include: 

  • A white or gray discharge 
  • Foul vaginal odor similar to rotten dish 
  • Vaginal or vulvar itching 
  • Burning with urination

Bacterial vaginosis can happen in any woman, but women with multiple sexual partners, women who douche, or women with low quantities of lactobacillus bacteria are at higher risk for getting this infection. The vaginal flora can also be affected by changes to immunity that are triggered by stress or anxiety, 

What causes it

Bacterial vaginosis occurs when there is an imbalance in naturally-occurring vaginal flora. This flora is mostly made up of lactobacillus bacteria. The main function of this bacteria is to maintain a slightly acidic vaginal pH to prevent illnesses. 

Decreased levels of lactobacillus bacteria in the vagina can happen due to:

  • Frequent vaginal douching 
  • Frequent sex 
  • Multiple sexual partners 
  • Having an IUD
  • Menstruation 

These situations can promote the growth of more harmful bacteria, like Gardnerella sp., Prevotella sp., Mycoplasma sp. e Ureaplasma sp., leading to a BV infection.

How to diagnose it

BV is usually found during a routine pap test or vaginal swab, although these tests can be ordered to confirm diagnosis if the woman is reporting symptoms. 

The follow criteria should be met to confirm a bacterial vaginosis infection:

  • White, homogenough vaginal discharge in copious amounts
  • Vaginal discharge with a pH over 4.5 
  • Foul vaginal odor
  • The presence of foreign bacteria and a microscopic change in epithelial cells of the vagina (also known as clue cells). These changes will especially be present with Gardnerella sp.

The doctor can also investigate for bacterial vaginosis through a urine test. Once confirmed, the doctor should start treatment promptly. 

Treatment options 

Treatment for bacterial vaginosis is usually done with antibiotics, like metronidazole. Medication can be prescribed for topical application (as an ointment), for vaginal insertion, or as pills to take orally. Antibiotics are prescribed for 7 days, or as indicated by the doctor. You should complete the full course without interruptions to prevent recurrence.

When treating, you should use a condom during all sexual contact and avoid the use of antibiotics. 

In addition, to prevent reinfection, you should avoid vaginal douching, use condoms during sex, avoid tight clothing, and use cotton underwear. Make sure you are perform all routine screening as recommended by your doctor. 

Complications if left untreated 

In most cases, bacterial vaginosis does not cause major complications. However, people with a weakened immune system are at higher risk for: 

  • Uterine or fallopian tube infection, which can lead to pelvic inflammatory disease 
  • AIDS infection if exposed to HIV 
  • Contracting a sexually transmitted infection like chalmydia or gonorrhea. 

In addition, if bacterial vaginosis is left untreated during pregnancy, there is a higher risk for spontaneous miscarriage, premature labour or low birth weight.