Everything You Need to Know About Bacterial Vaginosis

Just like your gut, your vagina is home to a variety of bacteria and needs to maintain a good balance to prevent infection. When there's an imbalance of bacteria, it can cause something ~super fun~ called bacterial vaginosis (BV).

According to the U.S. Department of Health & Human Services, BV is a condition caused by changes in the amount—usually an overgrowth—of certain types of bacteria in your vagina. The thing is, there isn't one specific type of bacterial overgrowth that leads to BV, says Kameelah Phillips, M.D., a board-certified obstetrician-gynecologist, and founder of Calla Women's Health. "In general, it's caused by a family of anaerobic bacteria (bacteria that doesn't grow or live when oxygen is present) that cause the odor, irritation, and discharge associated with BV," says Dr. Phillips.

These anaerobic bacteria include Gardnerella vaginalis, Prevotella Peptostreptococcus, and Bacteroides species. The ideal bacterial balance for your vagina is an acidic environment (a pH of <7) that promotes the growth of lactobacilli, including L. crispatus, L. gasseri, L. iners and L. jensenii, says Shweta Pai, M.D., a board-certified obstetrician-gynecologist and medical advisor at Love Wellness, a line of supplements, probiotics, and self-care products for women.

"Lactobacilli produces lactic acid, which helps maintain the acidic environment in the vagina. Low levels of lactobacilli, and therefore lactic acid too, allow the overgrowth of bacteria that cause BV and its associated symptoms," says Dr. Phillips. (

Common Symptoms of Bacterial Vaginosis

BV shares many of the same symptoms with a yeast infection, trichomoniasis (an STD), and urinary tract infection, so it's important to see your gynecologist for a proper diagnosis. "A hallmark of BV is a foul, fish odor. This doesn't mean that other infections aren't present, but this odor is classic for BV," says Dr. Phillips. Other bacterial vaginosis symptoms can include:

• White milky or gray vaginal discharge. It can be watery or foamy.
• Burning when urinating
• Itching around the outside of the vagina
• Vaginal irritation

However, Dr. Phillips says it's possible to have bacterial vaginosis and be asymptomatic. In fact, 84 percent of women with BV have no symptoms, according to the Centers for Disease Control and Prevention (CDC).

"The type of bacteria that causes BV can be present in low levels in the vagina and not cause other symptoms," she says. There currently isn't a routine screening for BV, but if you're experiencing symptoms or suspect you might have it, your gynecologist can check for BV and other vaginal infections by performing a vaginal swab, says Dr. Pai. (

Your gynecologist will insert a tool called a speculum (which is also used to do pelvic exams and Pap smears), into your vagina, and then use a cotton swab or wooden stick to collect a sample of your vaginal discharge, according to the U.S. National Library of Medicine. This sample will be sent to a lab for testing, which will help your doctor form a diagnosis and prescribe the right treatment for you.

The Causes of Bacterial Vaginosis

First things first: No, you can't contract BV from sitting on toilet seats, bedding, and swimming in pools, according to the CDC. Here are some things that can actually be the cause of bacterial vaginosis.

Douching and Using Vaginal Irritants

Most of the time, you can prevent BV by avoiding using certain soaps, douching, cleansing wipes, and other vaginal irritants, says Dr. Phillips. That's because using these products can disrupt the delicate pH balance of good bacteria in the vagina, which your vagina can achieve on its own. It might sound counterintuitive, but using these cleansing products can actually make things worse. (In fact, most people are good to go with just a good rinse of water and a clean hand.)

Dr. Pai says wipes or a gentle wash can be used if you want to post-workout, if you're not able to shower, or if you want to take some extra perineal (the area between your vulva and anus) hygiene measures—but they aren't necessary at all. "Using a natural, irritant-free cleansing wipe on the vulva area can provide you with some relief," says Dr. Pai. Be careful only to cleansing the vulva and perineal area and to avoid deep cleansing within the vaginal canal. (

You can maintain an ideal pH of 4 to 4.5 by avoiding vaginal irritants (such as douching and spermicides) and practicing perineal hygiene (read: not letting bacteria spread from your anus to your vag), says Dr. Pai. "But there are other things that can lead to BV that are out of our control, like age, genetics, intercourse, and menses."

Having Multiple Sex Partners

In addition to douching and using cleansing wipes, having multiple sex partners or a new one can cause BV, according to the Mayo Clinic. Although there isn't a clear link between sexual activity and BV, women with multiple sex partners are at higher risk for developing BV.

"Sexual activity can lead to BV because sperm is a vaginal irritant that can disrupt the vagina's delicate pH. Some studies have shown that having multiple partners or a new partner can lead to BV infections. This is likely due to the disruption in the vagina pH by new sperm," says Dr. Pai. (See: How Having Sex with a New Partner Can Mess with Your Vagina)

In fact, a September 2016 study in Sexually Transmitted Infections, which recruited 3,620 women between the ages of 15 and 44 years old, found that those who reported having a sexual partner who possibly or definitely had multiple other partners were more likely to be diagnosed with BV.

"If you're prone to BV infections, gently flushing the vagina with water after intercourse to remove semen can help prevent this disruption," says Dr. Pai. Dr. Phillips says having your partner wear a condom can also help prevent BV.

Hormonal Changes

While the CDC reports that BV is most common in women of child-bearing age, older women can experience it, too. According to a 2017 review in the Journal of Menopausal Medicine, postmenopausal women with low estrogen levels also have reduced levels of lactobacilli, which can lead to BV. These hormonal changes can affect the microflora in the vagina because estrogen promotes the colonization of the beneficial lactobacilli bacteria—so less estrogen can mean less of those good bacteria.

A 2014 study in The Journal of Gerontology also shows that BV is prevalent in postmenopausal women. The study was divided into two waves, in which women between the ages of 57 and 85 self-administered vaginal swabs to test for BV and Candida. Wave 2 vaginal swabs happened five years later. Results showed that BV was prevalent in 23 percent and 38 percent of women in Waves 1 and 2, respectively, suggesting that the prevalence of BV may increase with age.

BV is also common in pregnant women due to changes in hormones. The CDC reports that BV affects 25 percent of pregnant women. If left untreated, it can negatively affect the health of the baby. BV has also been associated with preterm birth, although it is not known for sure if (or why) this happens, according to JAMA.

Moreover, some women have reported having BV during the end of their period. This could be due to lower estrogen levels and instability of vaginal flora during menstruation, according to a 2000 study in Clinical Infectious Diseases. (

Smoking Cigarettes

Studies also show that smoking cigarettes can increase your risk of BV. A 2018 article in Scientific Reports suggests that women who smoke, and especially those who don't have enough lactobacilli, are more susceptible to urogenital infections like BV. More research is needed to understand how smoking can cause BV.

How to Treat Bacterial Vaginosis

The best course of treatment for BV is oral and transvaginal antibiotics, which include traditional drugs metronidazole and clindamycin, says Dr. Pai. Alternative treatment regimens include the antibiotics tinidazole or secnidazole. (Your doctor can prescribe these for you.)

"For refractory cases or cases that don't resolve with traditional antibiotics, boric acid [a mild anti-fungal and antiseptic] has been shown to have some benefit. Boric acid suppositories, like Love Wellness' The Killer (Buy It, $20, amazon.com), can safely alter the bacterial mucus in the vagina, thus removing the disease-causing organisms that antibiotics have a hard time getting rid of," says Dr. Pai.

Growing research also shows that taking probiotic supplements containing lactobacilli can be effective in preventing and treating vaginal imbalances that can lead to BV. "These treatments work by providing delivery of lactobacilli to the vagina. It's important that supplements have the specific lactobacilli that colonize the vagina and not the intestinal tract," says Dr. Phillips. For example, Jarro-Dophilus for Women probiotic (Buy It, $62, amazon.com) has specific lactobacilli strains for the vagina.

According to a 2019 systematic review in An International Journal of Obstetrics and Gynaecology, which evaluated 22 vaginal probiotics with Lactobacillus strains for BV, probiotics showed some promise for curing and preventing BV—but the probiotic strains didn't last beyond their dosing period, suggesting that the bacteria didn't colonize the vagina.

"When choosing a probiotic, it hasn't been proven that certain bacterial strains are superior to others in the scientific literature," says Dr. Pai. "However, there is limited data to suggest a probiotic with L. crispatus could provide benefit specifically for vaginal health." (

A 2019 trial in Beneficial Microbes recruited 40 women to test two different probiotic capsules, which contains Lactobacillus crispatus strains, and one placebo. After a week of treatment, there was a two-week washout period before starting the second treatment. Results showed that the probiotic capsules helped decrease the Nugent score, which is used to diagnose BV, suggesting that these strains show some promise for treating vaginal infections.

Moreover, in a 2003 randomized trial in FEMS Immunology & Medical Microbiology, 64 healthy women were given daily probiotics with Lactobacillus rhamnosus GR-1 and Lactobacillus fermentum RC-14 for 60 days. Results from the trial showed that the lactobacilli treatment helped 37 percent of the women, who had asymptomatic BV, restore a normal microflora.

The takeaway? "Although the studies [around probiotics] are small and limited within their scope, probiotics are a great, minimal-harm method to help promote a healthy vaginal and gut environment," says Dr. Pai. If you're interested in trying a probiotic for treating BV or maintaining vaginal health, consult your doctor first and ask if they can recommend one for you to try. Because supplements aren't regulated by the Food and Drug Administration, it's important to read labels carefully and ensure that they are third-party tested.

Regardless of which treatment your doctor chooses for you, the bottom line is it's important to treat the infection.

"Recurrent infections can negatively impact relationships if women feel self-conscious about the symptoms or avoid intimate contact. Also, the recurring infection can increase your risk for STDs so we would definitely want to address the issue," says Dr. Phillips.