Bacterial Vaginosis

An overgrowth of anaerobic bacteria that causes vaginal discomfort and other complications

Woman holding tipping scale representing bacterial vaginosis
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Here’s what you need to know about one of the most common vaginal conditions out there

What is bacterial vaginosis? 

Bacterial vaginosis (BV) occurs when unwanted bacteria overgrow and disrupt your vaginal microbiome. It is a common cause of vaginitis which is an inflammation of the vagina [1]. 

While most women with BV have symptoms that are difficult to ignore, others might have it without showing any symptoms. This is known as asymptomatic BV. The verdict is out on whether or not these women are at risk for complications from BV, or if they are perfectly healthy [6]. What constitutes a normal vaginal microbiome might even vary according to your ethnicity, putting certain groups at higher risk [7]. Current research doesn’t completely understand this, and Juno Bio is working to fill some of the gaps in this kind of information. 

How common is it?

The CDC estimates that 29.2% of American women between the ages of 15 and 49 have BV. About half of them are asymptomatic [1]. 

What causes BV and what are the risk factors?

BV occurs when your vaginal microbiome is out of balance and bad bacteria outnumber good bacteria. This means that instead of having a lot of lactobacillus (a protective type of good bacteria), you end up with overgrowth of naturally occurring anaerobic bacteria that can live without any oxygen like Gardnerella vaginalis or Atopobium vaginae. This is part of what makes BV hard to diagnose – because different bacteria are present, you can’t test for a specific bacterium to confirm a diagnosis like you would with an STI [2, 3]. 

The end result is a combination of disruptive symptoms such as abnormal discharge, itching, pain during sex or while urinating, and a less-than-pleasant odor.

A number of things can throw off the normal balance of your vaginal bacteria and put you in a state of vaginal dysbiosis. The main culprits that put you at risk for BV are [1,2]:

  • Having sex with multiple partners (regardless of gender) or with a new partner 
  • Douching
  • Naturally being low in lactobacillus. Again, more research needs to be done in this area
  • Having low oestrogen, such as from losing one or both ovaries, which cuts the production of the good bacteria’s food source glycogen
  • Hormonal changes such as during menstruation which causes an increase in your vaginal pH, or during menopause

What are the symptoms?

All of the usual suspects related to vaginitis might make an appearance [1,2]. These include:

  • Itching
  • Pain during sex or urination
  • Abnormal discharge. For BV, it will usually be white or grey and much thinner than you would have with a yeast infection [4] and is commonly described as fishy-smelling.

How is it diagnosed?

If your symptoms match those described above, your doctor can perform a vaginal pH test. Anything above 4.5 is too high and considered unhealthy. A sample might also be taken from your discharge to look at what cells (like human clue cells) or bacteria (gram-negative or gram-variable bacteria) might be present in the vaginal microbiome. [1, 2, 4] 

What are the treatment options?

Once diagnosed, your doctor may prescribe antibiotics such as metronidazole or clindamycin to clear the BV [1]. These can be administered as pills or vaginal suppositories depending on the medication. Some research indicates that probiotics might also be helpful to help repopulate the vagina with healthy lactobacilli. 

Even with treatment, it’s common for BV to re-appear after 3 to 12 months. Why this happens is yet another research grey area.

Can BV lead to other complications?

Even when symptoms feel manageable, you definitely want to get a proper diagnosis since the lack of lactobacilli is linked with an increased risk of STIs. BV can also lead to Pelvic Inflammatory Disease (an infection of the upper genital tract including the uterus), a pretty serious condition that can even lead to fertility issues [5]. For pregnant women, BV can result in preterm birth. 

What can be done to prevent BV?

To avoid BV from cropping up in the first place, practice safe sex by always discussing sexual health with your partner, using barrier protection correctly (such as a condom or dental dam), and getting tested regularly. To protect yourself against infections, avoid disrupting the balance of protective bacteria in the vaginal microbiome by limiting the use of douches as well as the use of scented soaps, tampons or pads, try to avoid anything that irritates your vagina or upsets the pH balance.

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1. Bacterial Vaginosis - STD information from CDC [Internet]. 2020 [cited 17 September 2020]. Available from:

2. Bacterial vaginosis - Symptoms and causes [Internet]. Mayo Clinic. 2020 [cited 17 September 2020]. Available from:

3. Bacterial vaginosis [Internet]. 2020 [cited 17 September 2020]. Available from:

4. Bacterial Vaginosis and Desquamative Inflammatory Vaginitis. New England Journal of Medicine. 2019;380(11):1088-1089.

5. Haggerty C, Ness R, Totten P, Farooq F, Tang G, Ko D et al. Presence and Concentrations of Select Bacterial Vaginosis-Associated Bacteria Are Associated With Increased Risk of Pelvic Inflammatory Disease. Sexually Transmitted Diseases. 2020;47(5):344-346.

6. Gibbs R. Asymptomatic bacterial vaginosis: is it time to treat?. American Journal of Obstetrics and Gynecology. 2007;196(6):495-496.

7. Wells J, Chandler R, Dunn A, Brewster G. The Vaginal Microbiome in U.S. Black Women: A Systematic Review. 2020.

Written by Aisha Ommaya, science comms officer with Juno Bio

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