What Is Bacterial Vaginosis? Everything You Need to Know About Symptoms, Causes, Diagnosis, Treatment, and Prevention

Bacterial vaginosis (BV) is a common condition that can be caused by an imbalance between the “good” and “harmful” bacteria that are normally found in a woman’s vagina. It’s the most common type of vaginal infection in women ages 15 to 44.

Bacterial vaginosis is surprisingly prevalent among pregnant women: Up to 19 percent of expectant mothers in the United States have BV.

Signs and Symptoms of Bacterial Vaginosis

Some women with bacterial vaginosis don’t have any symptoms. Others have symptoms that may include:

A thin white, dull gray, or greenish vaginal discharge
A strong, foul (often fishy) odor, especially after sex
Vaginal itching or irritation
A burning sensation during urination

Causes and Risk Factors of Bacterial Vaginosis

BV happens when there’s an imbalance between good (healthy) and bad (disease-causing) bacteria in the vagina.

Gardnerella is the bacteria most often associated with bacterial vaginosis; between the lack of “good” bacteria, such as lactobacilli, and the overgrowth of Gardnerella or other harmful bacteria, symptoms of BV infection can result. Anything that alters the vagina’s pH balance can alter bacteria levels and set the stage for BV. This means that douching or using vaginal deodorants can lead to BV.

Research from 2019 found that women who are overweight or obese have a greater occurrence of BV than lean women do.

Having a new sex partner or multiple partners can increase a woman’s risk of developing bacterial vaginosis.

Indeed, new research suggests that a man’s penile microbiome — the community of bacteria in and around the penis — could predict whether his female partner develops BV.

How Is Bacterial Vaginosis Diagnosed?

Your healthcare provider will examine your vagina for signs of discharge that would suggest BV. Then, he or she will take a sample of fluid from the vagina and examine it under a microscope, use an in-office test, or send it to a lab to check for the presence of harmful bacteria.

Prognosis for Bacterial Vaginosis

Sometimes BV will go away without treatment, but not treating the infection can involve serious health risks. Untreated BV can increase a woman’s risk of getting sexually transmitted infections, such as HIV, herpes, gonorrhea, and chlamydia. The latter infections can increase a woman’s risk of developing pelvic inflammatory disease (PID), including inflammation of the uterus, fallopian tubes, and even the ovaries, which can have a negative effect on fertility.

What’s more, research from 2013 suggests that recurrent BV, in particular, can have a negative effect on a woman’s self-esteem — making her feel embarrassed and self-conscious — and affect her sex life.

If BV occurs during pregnancy, a woman is more likely to deliver her baby early (prematurely) or with low birth weight (meaning less than 5.5 pounds at birth).

That’s why symptomatic BV needs to be treated during pregnancy.

Duration of Bacterial Vaginosis

Once BV is treated with antibiotics, it usually goes away. But sometimes it persists or recurs, often within three months, for reasons that aren’t entirely understood. If a person keeps getting BV, a longer course of antibiotics may be necessary.

Treatment and Medication Options for Bacterial Vaginosis

Women with symptoms of BV should be treated for the infection, not only to relieve symptoms but also to prevent complications.

Medication Options

Recommended medication treatment options include:

Metronidazole (Flagyl), 500 milligrams (mg), orally twice a day for seven days
Metronidazole gel (MetroCream), 0.75 percent, one full applicator inserted vaginally, once a day for five days
Clindamycin cream (Cleocin T), 2 percent, one full applicator inserted vaginally at bedtime for seven days

Other medical treatments include:

Tinidazole (Tindamax), 2 grams (g), orally once a day for two days
Tinidazole, 1 g, orally once a day for five days
Clindamycin (Cleocin Hcl), 300 mg, orally twice a day for seven days
Clindamycin ovules (Cleocin), 100 mg, inserted vaginally at bedtime for three days

Alternative and Complementary Therapies

During treatment and for 24 hours after completion of treatment, alcohol should be avoided while taking metronidazole or tinidazole. Women should refrain from sexual activity or use condoms during treatment; but clindamycin cream, which is oil-based, may weaken latex condoms and diaphragms for five days after use.

While some studies have evaluated the use of vaginal suppositories containing lactobacillus or other probiotic formulations to treat BV, there’s no evidence supporting these as a replacement therapy in women with BV.

Even after treatment, it’s not uncommon for BV to persist or recur for reasons that aren’t entirely understood. One study found that 58 percent of women who were treated for symptomatic BV had a recurrence within a year.

To effectively treat recurrent BV, your doctor may prescribe an extended course of antibiotics.

In some cases, taking oral or vaginal probiotics may help prevent recurrent BV but ask your doctor before trying any supplements.

Prevention of Bacterial Vaginosis

Researchers don’t understand exactly how BV occurs, but there are some measures that may lower your risk. First, take steps to keep the bacterial populations in your vagina balanced by using only warm water to wash, avoiding soap, wiping only from front to back when you’re using the toilet, and wearing cotton or cotton-lined underpants. Avoid vaginal deodorants and douching, which upset the balance of good to harmful bacteria in ways that may increase your risk of developing BV.

It also may help to practice safe sex by using condoms and getting tested for STIs.

Complications of Bacterial Vaginosis

If left untreated, BV can increase your risk for sexually transmitted infections (STIs) such as herpes, gonorrhea, chlamydia, and HIV.

It also can cause other problems (such as having a low-birth-weight baby or premature rupture of the membranes) during pregnancy.

RELATED: A His-and-Hers Sexual Health Issue

Research and Statistics: How Many People Have Bacterial Vaginosis?

Bacterial vaginosis is one of the most common types of vaginal conditions, affecting an estimated 29 percent of women ages 14 to 49. It’s also prevalent among pregnant women: Up to 19 percent of expectant mothers in the U.S. have bacterial vaginosis.

Racial Disparity in Bacterial Vaginosis

Data suggests that African American women experience BV more frequently than women of European ancestry. But the basis for this racial disparity is not understood. Differences in known risk factors, such as a history of smoking, do not explain the racial difference in the occurrence of BV. More research is needed.

According to an analysis of women who participated in the National Health and Nutrition Examination Survey (NHANES) 2001–2004, 51 percent of non-Hispanic Black women, 32 percent of Mexican American women, and 23 percent of non-Hispanic white women reported experiencing BV.

Related Conditions and Causes of Bacterial Vaginosis

If left untreated, bacterial vaginosis can increase a woman’s risk of developing other medical conditions, including:

Sexually Transmitted Infections Having BV makes a woman more susceptible to sexually transmitted infections such as HIV, herpes, chlamydia, or gonorrhea.
Pelvic Inflammatory Disease BV can increase the risk of STIs, which can sometimes lead to PID, an infection of the uterus, fallopian tubes, and ovaries that can impair fertility.
Preterm Birth During pregnancy, bacterial vaginosis is linked to premature deliveries and low birth weight babies.

Resources We Love

To learn more about BV, check out the following websites.

Planned Parenthood

A reliable source of information about reproductive and sexual health and healthcare, Planned Parenthood provides vital facts about women’s health and wellness, sexually transmitted infections, birth control, pregnancy, and more.

American College of Obstetricians and Gynecologists (ACOG)

ACOG is a go-to source for research-supported information about women’s reproductive health issues, including fertility, conception, pregnancy, and best practices for each of these issues.