What is bacterial vaginosis?
Bacterial vaginosis (commonly known as BV) is the most common vaginal infection in women of childbearing age. It's caused by an imbalance in the bacteria that live in your vagina. About 1 in 4 women have this infection at some point during pregnancy, though estimates vary widely.
Normally, "good" bacteria, called lactobacilli, are in the majority and keep other kinds of bacteria in check. You end up with BV when there are too few lactobacilli, allowing other bacteria to grow out of control.
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According to the U.S. Department of Health & Human Services Office on Women's HealthOpens a new window, expecting moms may be more at risk for BV because of the hormonal changes that happen during pregnancy. Shifting hormone levels can change the balance of bacteria in the vagina, says the American College of Obstetricians and GynecologistsOpens a new window (ACOG).
How does having BV affect my pregnancy?
Most women with BV have perfectly normal pregnancies. And up to half of the cases of BV in pregnant women resolve on their own.
Still, studies have shown that having BV when you're pregnant is associated with an increased risk of:
But the link between BV and pregnancy complications isn't perfectly clear. Experts don't yet know why only some women with BV end up delivering prematurely. They also don't know if BV directly causes complications such as PPROM or if women who are predisposed to other infections or problems that may lead to these complications are also more likely to have BV.
Having BV does make you more susceptible to certain sexually transmitted infections (STIs), such as genital herpes, chlamydia, gonorrhea, and HIV, if you're exposed to them.
In women who aren't pregnant, BV has been linked to an increased risk of pelvic inflammatory disease (PID) and infections after gynecologic surgery. (It's possible to get PID during pregnancy, but it rarely happens.)
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What are the symptoms of BV?
At least half the women who get BV have no symptoms at all. If you do have symptoms, you might notice:
- A thin white or gray discharge
- A strong, fishy smell. This odor is most apparent after sex, when the discharge mixes with semen.
- Itching or irritation in your genital area
- Burning when you urinate
Let your healthcare provider know if you have these symptoms. They'll examine a sample of your vaginal fluid and cervical secretions to see if you have BV or another infection, and they'll prescribe medication accordingly.
Will I be screened for BV if I don't have symptoms?
If you're at low risk for premature delivery
If you don't have symptoms and are at low risk for giving birth prematurely, you won't be screened for BV.
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Although women with BV may be more likely to have a preterm delivery and antibiotics can clear up the infection most of the time, almost all research to date shows that treating symptom-free cases of BV in women who haven't had a previous preterm delivery doesn't lower their chances of delivering early.
For this reason, the U.S. Preventive Services Task Force (USPSTF), the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Family Physicians (AAFP), and a number of other experts agree for now that screening isn't worthwhile for this group of women.
If you're at high risk for premature delivery
If you don't have symptoms of BV but are at high risk for preterm delivery, your caregiver may or may not screen you at your first prenatal visit. Experts debate whether it's beneficial to do so because the evidence is conflicting.
In a 2020 statementOpens a new window, the USPSTF concluded, "the current evidence is insufficient to assess the balance of benefits and harms of screening for bacterial vaginosis in pregnant persons at increased risk for preterm delivery." There are some specialists, though, who recommend screening for certain high-risk women. Everyone agrees that more research is needed in this area.
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How is BV treated during pregnancy?
Don't try to treat a BV infection by yourself with over-the-counter medications.
If you're diagnosed with BV, you'll be given a course of antibiotics that are considered safe to take during pregnancy. (Unlike with some other infections, your partner won't be treated.)
It's important to take all of the medicine that you've been prescribed, even if any symptoms have gone away. In most cases, this will clear up the infection in your vagina and any symptoms you might have, though unfortunately the infection may recur at some point.
In fact, up to 30 percent of women have symptoms again within three months and over half of women have a recurrence within a year. Antibiotics usually kill off most of the bacteria that cause BV, but there's no way to get the "good" bacteria to grow back faster so they can hold the "bad" bacteria in check.
Let your practitioner know if your symptoms come back. Your second round of treatment may be a longer course of a different medication.
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Experts are studying treatments that replenish beneficial bacteria in women with recurrent cases of BV. More studies are needed, but early findings look promising.
How can I avoid getting BV?
Because no one knows what causes this bacterial imbalance, there's nothing definitive you can do to protect yourself from bacterial vaginosis. However, there are a few ways you can reduce your risk of getting BV:
- Follow safe-sex practices if either you or your partner have sex with other people. It's not clear what role sexual activity plays in triggering BV, but it's rare in women who've never had sex and is most common in women with multiple sex partners and in gay women. Cover sex toys with condoms when possible, and clean them after every use. If your partner has BV, use a dental dam during oral sex.
- If you smoke, here's another reason to quit: Smoking cigarettes increases your risk for BV.
- Don't douche or use feminine hygiene sprays or scented soaps on your genitals. These products may upset the delicate balance of bacteria in your vagina. (Douching isn't safe during pregnancy anyway. In extremely rare cases, douching may force air to pass beneath the membranes of the amniotic sac and enter your circulation, causing an air embolism that can be life threatening.)
BV isn't usually a problem during pregnancy, but it's good to know when it might be and how to reduce your risk. Here's an article to fill you in on other infections that can affect pregnancy.
Learn more:
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