Symptoms of Bacterial Vaginosis

Bacterial vaginosis can be aggravating for the more than 3 million American women who suffer from it each year. The condition, triggered by bacterial overgrowth, is common in women 15 to 44 and can lead to vaginal discharge, itchiness, burning, and a "fishy" odor. If left untreated, bacterial vaginosis can increase your vulnerability to sexually transmitted infections and may, in some cases, lead to preterm birth or even miscarriage.

Knowing the signs of bacterial vaginosis is your single best defense to avoiding complications.

bacterial vaginosis symptoms
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Frequent Symptoms

Bacterial vaginosis (BV) is caused by an imbalance of the naturally occurring bacteria in the vagina and, most specifically, a decline of a type of "good" bacteria known as lactobacilli. When this happens, other "bad" bacteria can predominate and cause infection.

Of the 21 million women in the United States who develop BV each year, as many as 84% will have no symptoms, according to a report from the Centers for Disease Control and Prevention.

Of those that do, the most common include:

  • A grayish white or yellow discharge that usually coats the walls of the vagina
  • A "fishy" smell that can get often worse after intercourse
  • A burning sensation when urinating
  • Vaginal itchiness, redness, and swelling (usually mild)
  • Vaginal bleeding after intercourse

Even after a woman has been successfully treated for BV, as many as 50% will experience a recurrence of symptoms within a year.

Rare Symptoms

On rare occasions, BV may cause dysuria (painful or difficult urination) or dyspareunia (painful intercourse). These are most often caused by a secondary infection of the urinary tract and vagina.


Diagnosing and treating BV is important as it can greatly reduce the risk of complications. The three most common concerns are the increased risk of sexually transmitted infections (including HIV), pelvic inflammatory disease (PID), and pregnancy loss or preterm birth.

Sexually Transmitted Infections

Bacterial vaginosis is characterized by the inflammation of vaginal tissues. When this occurs, the tissues and underlying blood vessels will start to swell and expand to allow larger immune cells closer to the site of infection.

While this process is vital to healing, it also has a downside: It makes these tissues more permeable and vulnerable to sexually transmitted infections. This is especially true when BV symptoms are severe.

According to a 2018 study from the St. Louis School of Medicine, symptomatic BV increases the risk of gonorrhea, chlamydia, and trichomoniasis by 270 percent.

The same appears to be true with genital herpes and syphilis; the relationship between BV and the human papillomavirus (HPV) is somewhat less clear. By contrast, women with subclinical BV (in which there are no observable symptoms) were not seen to be at an increased risk.


By contrast, the relationship between BV and HIV is not only clear but insidious. HIV is a disease associated with the rapid depletion of immune cells called CD4 T-cells. When BV occurs, white blood cells will flood the vaginal tissue in order to surround and contain the bacterial infection. 

However, if HIV is present, those same white blood cells will "capture" the viruses and carry them back to the CD4 T-cells to be neutralized. But, instead of being killed, HIV will turn the table on the CD4 T-cells and infects them instead.

In the end, having a BV infection helps facilitate HIV by providing it more targets for infection.

And, it's not just women who are at risk. If a woman has HIV, the development of BV can lead to a phenomenon known as viral shedding in which a genital infection will inherently increase the concentration of HIV in semen or vaginal secretions. If this occurs, a woman will be more likely to pass the virus to a sexual partner (in some cases, even if she is on HIV therapy).

Pelvic Inflammatory Disease

Pelvic inflammatory disease (PID) is caused when a bacterial infection in the vagina passes through the cervix and enables the spread of infection to the uterus and fallopian tubes.

While there has been some debate as to the relationship between BV and PID, 2013 evidence suggests that PID is most likely to affect women under 25 who either have severe or recurrent bouts of BV.

PID is characterized by pelvic and abdominal pain, often long-term. Severe complications include:

  • The development of scar tissue both outside and inside of the fallopian tubes which can lead to tubal blockage
  • Ectopic pregnancy (a pregnancy that develops outside of the womb)
  • Infertility

Pregnancy Complications

Bacterial vaginosis during pregnancy may also increase the risk of preterm birth and miscarriage (most often in the second trimester). Other commonly cited risks include low birth weight and the premature rupture of membranes (PROM). Even a low-level bacterial infection can weaken fetal membranes and lead them to rupture. If this occurs before 33 weeks, it would require aggressive interventions to prevent labor, avoid fetal infection, and aid in the development of the baby's lungs.

The association between BV and pregnancy complications is not entirely clear. Some scientists have questioned whether BV directly triggers these events (since the vast majority of pregnant women with BV have normal births) or if other complications facilitated by BV are to blame.

With that being said, current evidence suggests that the development of BV in the second trimester may increase the risk of preterm birth by 60 percent and lead to a seven-fold increase in the risk of PROM. By contrast, the appropriate use of antibiotics is seen to decrease the risk, often to negligible levels.

In terms of safety, the oral and topical antibiotics used to treat BV (metronidazole, clindamycin, tinidazole) pose no risk to the developing fetus. However, clindamycin cream does carry a slight risk of preterm birth and is therefore avoided during pregnancy.

When to See a Doctor

Since most complications of BV occur with symptomatic disease, it is important to see a doctor if any of the characteristics signs appear. You should never try to self-diagnosis as this can lead to inappropriate treatment.

Bacterial Vaginosis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

It is even more important to seek care if you have a fever, body aches, pelvic and/or abdominal pain, or difficulty urinating. All of these things can be a sign of a more serious infection.

If you are pregnant and experience symptoms of BV, call your OB/GYN. Early diagnosis and treatment can go a long way to ensuring a safe and event-free pregnancy.

Frequently Asked Questions

What are the symptoms of bacterial vaginosis?

Bacterial vaginosis (BV) is caused by a bacterial imbalance in the vagina, which may lead to symptoms of infection. However, BV may also cause no symptoms in up to 84% of cases.

The most frequent symptoms include:

  • Vaginal itching and redness
  • A fishy or foul-smelling discharge that may increase after sex
  • Grayish or yellow discharge
  • A burning sensation when urinating
  • Vaginal bleeding after intercourse

How can I tell if I have bacterial vaginosis or a yeast infection?

The hallmark symptom of BV is the characteristic "fishy" odor and gray or yellow color of the discharge. A yeast infection may present with similar symptoms, such as itching, redness, and burning when urinating, but most notably presents with thick, lumpy, white, cottage-cheese-like discharge that usually doesn't have a strong odor.

How did I get bacterial vaginosis?

Researchers and medical experts don't know what triggers BV in most people, but certain risk factors have been identified, such as having multiple sexual partners, unprotected sex, douching, smoking, having an intrauterine device (IUD), and undergoing hormonal changes, such as pregnancy and menopause.

Can bacterial vaginosis clear up without treatment?

Yes. In some cases, BV can clear up on its own, as changes in vaginal pH can restore flora balance between healthy and unhealthy bacteria. However, if you have symptoms, getting diagnosed and treated by a physician can help clear up the infection sooner.

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Article Sources
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  1. Centers for Disease Control and Prevention. STD facts - bacterial vaginosis. Updated Feb 8, 2017.

  2. Jones A. Bacterial Vaginosis: A Review of Treatment, Recurrence, and Disparities. The Journal for Nurse Practitioners. 2019;15(6):420-423. doi:10.1016/j.nurpra.2019.03.010.

  3. Jennings LK, Krywko DM. Pelvic Inflammatory Disease (PID). Treasure Island, FL: StatPearls Publishing; 2019.

  4. Reiter S, Kellogg Spadt S. Bacterial vaginosis: a primer for clinicians. Postgrad Med. 2019;131(1):8-18. doi:10.1080/00325481.2019.1546534

  5. Centers for Disease Control and Prevention. BV statistics. Updated Feb. 10, 2020.

  6. Centers for Disease Control and Prevention. Vaginal candidiasis. Updated November 10, 2020.

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