Photography by Laura Tancredi
Bacterial Vaginosis: a common reason for irregular vaginal discharge
Top things to know:
The balance of bacteria in your vagina plays a key role in your reproductive and overall health
Bacterial vaginosis (BV) is the most common cause of unusual vaginal discharge and odor in people who seek care
Reduce your risk by avoiding douching, using condoms, and skipping soap in and around your vulva
BV can be treated with a course of antibiotics, pH-restoring medications, and sometimes probiotics
What is bacterial vaginosis (BV)?
If you’d never heard of bacterial vaginosis until you started googling your discharge, you’re not alone. Typically, a healthy vagina is mostly populated by Lactobacillus bacteria, which make up over 70% of the vaginal microbiome (1,2). These bacteria help keep your vagina slightly acidic, protecting against infections and maintaining balance (1,2).
BV happens when that balance shifts, causing an overgrowth of a group of bacteria called anaerobes, which thrive without oxygen. The most common culprit? Gardnerella (3). (And no, it’s not the same thing as gonorrhea—they’re completely different).
When the bacterial balance changes, so do the chemical byproducts. This can lead to symptoms like:
An unpleasant or fishy smell
Watery or grayish discharge
Itching or irritation in the vagina or vulva (4)
For some people, BV can also cause inflammation and an immune response that weakens the natural mucus barrier of the vagina. This can increase the risk of getting other infections, including STIs like HIV and chlamydia (3,5).
In many cases, the most significant impacts of symptomatic BV are emotional and social. This is especially true for people whose BV is recurrent (having it multiple times, despite treatment) (6). One study found that depending on the severity and frequency of symptoms, BV can lead people to feel embarrassed, ashamed, dirty, and very concerned that others may detect their malodor and abnormal discharge (6). It can affect a person’s self-esteem and sex life, to the point that they may avoid sexual activity altogether. Recurrent symptoms of BV, without an understanding of the reason, can be frustrating and make someone feel out of control.
While BV doesn’t usually lead to health complications, untreated BV can sometimes result in pelvic inflammatory disease, infection after gynecologic surgery, and pregnancy complications, including miscarriage and preterm birth (3,8,9).
How common is BV?
BV is the most common reason people seek care for unusual discharge or odor. Researchers estimate that about 3 in 10 of people with vaginas in the US have BV at any given time. It’s a little more common in certain groups: around 2 in 5 Caucasians, 3 in 10 Mexican Americans, and 5 in 10 African Americans (7). Many people don’t even know they have it, as roughly 8 in 10 cases don’t cause noticeable symptoms (7).
The chances of having BV can vary based on factors such as race, ethnicity, income, and education level (7,10).
What causes BV?
BV is still somewhat of a mystery—even to scientists. While we know that different things inside and outside the body can throw off the vaginal microbiome, we still don’t fully understand why one person gets BV and another doesn’t (4).
Some things that may increase your risk include:
Douching: People who have douched (flushed the vagina with water, soap, or antiseptic) in the past six months are much more likely to get BV (7)
Prolonged or unpredictable bleeding: Menstrual blood raises vaginal pH and lowers Lactobacillus levels, making it easier for BV-associated bacteria to grow (10,11)
Having an IUD (copper or hormonal) (5)
New or multiple sex partners (4)
Receiving anal sex before vaginal sex without changing the condom (12–14)
People who use hormonal birth control, like the pill, may have a lower risk of BV. This could be due to its stabilizing effect on hormone levels and menstrual patterns (7,10,15).
Why do I get BV after my period?
Some people notice symptoms of BV after their period. This is because menstrual blood changes the pH of the vagina so it becomes less acidic (10,11). It also dilutes the helpful Lactobacillus bacteria (10,11). This can give anaerobic bacteria a chance to take over, especially if your vaginal flora was already a little out of balance.
Some people also notice symptoms of BV before their period, which could be tied to hormonal fluctuations in this second half of the cycle (the luteal phase), but more research is needed (15).
What can be mistaken for BV?
BV isn’t the only reason for changes in vaginal discharge. Here’s a quick guide to what else it could be (16):
Bacterial Vaginosis (BV)
Discharge: Thin, gray, or white
Odor: Fishy or unpleasant
Itching or irritation: Sometimes
Other notes: Often worse after sex or menstruation
2. Yeast infection
Discharge: Thick, white (cottage cheese-like consistency)
Odor: No strong odor
Itching or irritation: Common
Other notes: May cause swelling or burning
Discharge: Frothy, yellow-green
Odor: Foul-smelling
Itching or irritation: Possible
Other notes: An STI that requires treatment
4. Typical discharge variation
Discharge: Clear or white. Color and texture changes throughout the cycle
Odor: Mild to none
Itching or irritation: None
Other notes: Typical discharge varies by person and phase of cycle
If you’re not sure what’s going on, it’s best to check with a healthcare provider before trying to treat it yourself.
Is BV an STI?
Sort of—but it’s complicated.
Bacterial vaginosis isn’t classified as a sexually transmitted infection (STI) because you can get it even if you’ve never had sex. But sexual activity—especially with new or multiple partners— can disrupt the vaginal microbiome and increase your risk of BV (4,5).
A study published in 2025 looked at heterosexual couples where the woman had BV. Researchers found that when male partners were treated with both oral antibiotics and a topical cream, the woman’s chances of BV coming back dropped significantly (18). This suggests that BV-associated bacteria can be shared between partners, and treating just one person might not be enough.
So while BV itself isn’t an STI, it is sexually associated. Using condoms, avoiding re-exposure from untreated partners, and talking to your healthcare provider about partner treatment can all help—especially if you’re dealing with recurrent BV.
Why do I keep getting BV?
BV can be really stubborn. Hormonal shifts, sex, and even small changes in your routine can throw off your vaginal balance (4,5). If it tends to pop up around your period or after sex, those might be your triggers.
Unfortunately, recurrence is super common. More than 1 in 2 people who treat their BV will have it come back within six months (19). It’s not your fault. It just means we need better long-term treatments. If you have a sexual partner(s), they might need treatment too.
How to prevent BV
Here are some ways to lower your chances of getting BV or having it come back (4,5,18):
Use condoms or dental dams during sex
Avoid douching (even the “natural” kind)
Skip soaps, washes, and scented products in and around your vulva
Rinse your vulva with water only, or use a gentle, unscented, non-foaming cleanser if needed
Change out of wet or sweaty clothes quickly
Track your BV symptoms in Clue to spot patterns, like around your period
Consider simultaneous treatment if you have a partner (or partners)
Talk to your healthcare provider if symptoms keep coming back
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How to treat BV
Treatment for BV depends on your symptoms and history. Most of the time, it includes:
Antibiotics
Antibiotics are the primary treatment for BV. Common options include:
Metronidazole: Taken as a pill for 7 days, or applied as a vaginal gel for 5 days (4).
Clindamycin: Taken as a pill for 7 days, or applied as a vaginal cream for 7 days (4).
These treatments are usually highly effective at relieving symptoms and restoring the vaginal microbiome (20).
Vaginal pH Regulators
Lactic acid gels help maintain a healthy vaginal pH, creating an environment where beneficial Lactobacillus bacteria can thrive. Some research suggests they may be helpful, particularly for symptom relief or recurrence prevention, but they are not a substitute for antibiotics in treating active infections (21).
Probiotics
Probiotics containing Lactobacillus species may support vaginal health, particularly when used alongside antibiotic treatment (22). However, results from studies have been mixed. Probiotics are currently considered supportive care, not a standalone treatment (23).
Some treatments are prescription-only, while others—like lactic acid gels—are available over the counter. Tracking your symptoms in Clue can help your provider figure out what’s triggering your BV.
If BV keeps coming back, talk to your healthcare provider. You might need a longer course of treatment or a combination of different approaches. Researchers are working on better options, but we're not quite there yet.
Talk about it
There’s no shame in having BV. It doesn’t make you dirty, and it doesn’t mean you’re doing anything wrong. Vaginal infections are really common, and the stigma around them can make people feel isolated. If you feel comfortable, talk to your partner(s) and friends about it. The more we talk about BV, the less power the stigma has.
Know your discharge. Track changes in Clue and stay on top of your vaginal health.
FAQs
Why do I get BV after sex?
Sex (especially unprotected or with a new partner) can disrupt the vaginal microbiome. Semen is alkaline, which can shift your pH and give anaerobic bacteria a chance to grow (4,5).
Why does my partner keep giving me BV?
We don’t know for sure if partners can directly "give" you BV, but sexual activity without a barrier is linked to higher recurrence (4,5). Using condoms or dental dams may help, and it’s a good idea for partners to get treated too.
Does BV clear up on its own?
Sometimes. Mild or asymptomatic BV can clear up without treatment (4). But if you have symptoms—or if it keeps coming back—it’s best to talk to a healthcare provider.
