Bacterial vaginosis, often called BV, is the most common vaginal condition in women of reproductive age. It happens when the natural balance of bacteria in the vagina shifts, allowing certain bacteria to overgrow while others decrease. This is not a sexually transmitted infection, though sexual activity can increase the risk of developing it.
What Is BV For Females?
BV is a disruption of the normal vaginal microbiome. A healthy vagina is dominated by Lactobacillus bacteria, which produce lactic acid and hydrogen peroxide. These keep the vaginal environment acidic and prevent harmful bacteria from taking over.
When something disturbs that balance, other bacteria like Gardnerella vaginalis and Atopobium vaginae multiply rapidly. The result is a shift from a healthy acidic environment to a less acidic one. This overgrowth triggers the symptoms most women notice.
BV is not a yeast infection and it is not a sexually transmitted disease. It is a bacterial imbalance. Up to 84% of women with BV experience no symptoms at all, according to the Centers for Disease Control and Prevention. Many women only learn they have it during a routine pelvic exam or Pap smear.
What Are the Symptoms of Bacterial Vaginosis?
The most recognizable symptom is a thin, grayish-white vaginal discharge. Many women describe it as having a strong “fishy” odor, especially after sex or during menstruation. The smell happens because the overgrown bacteria produce amines, chemical compounds that release a fishy scent when they become alkaline.
Other possible symptoms include:
- Mild vaginal itching or irritation
- A burning sensation during urination
- Discomfort during intercourse
- No symptoms at all in many cases
The discharge in BV is distinctly different from a yeast infection. Yeast infections typically cause thick, white, cottage-cheese-like discharge with intense itching. BV discharge is thin and watery. If you are unsure which condition you have, a medical evaluation is necessary because self-treatment with the wrong medication will not work.
What Causes BV and Who Gets It?
The exact trigger for the bacterial shift is not fully understood. Researchers do know several factors increase the likelihood of developing BV.
Douching is one of the strongest risk factors. It washes away the protective Lactobacillus bacteria and alters the natural pH of the vagina. The American College of Obstetricians and Gynecologists advises against douching for any reason.
Sexual activity plays a role. Women who have a new sexual partner or multiple partners are more likely to develop BV. Condom use appears to reduce the risk. Women who have sex with women can also develop BV, and the condition may be shared between female partners.
Other risk factors include smoking, using intrauterine devices for contraception, and hormonal changes from menstruation or pregnancy. Having a female partner with BV also increases risk. BV is not caused by poor hygiene, and it cannot be acquired from toilet seats, swimming pools, or shared towels.
Why Treat BV If It Does Not Always Cause Symptoms?
Untreated BV can lead to serious health complications, even when a woman feels fine. The bacterial imbalance makes the reproductive tract more vulnerable to infection.
Women with BV have a higher risk of acquiring sexually transmitted infections, including HIV, chlamydia, and gonorrhea. The condition also increases susceptibility to the herpes simplex virus. The protective acidic barrier is compromised, making it easier for pathogens to enter the body.
For pregnant women, BV carries additional risks. Research consistently shows BV is linked to preterm birth, low birth weight, and miscarriage. Some studies indicate that treating BV in pregnant women with symptoms may reduce these risks, though routine screening of all pregnant women remains a topic of ongoing debate in the medical community.
BV also increases the risk of pelvic inflammatory disease (PID), an infection of the upper reproductive organs that can cause chronic pelvic pain and damage the fallopian tubes. PID from BV is a leading cause of tubal factor infertility.
Finally, BV increases the risk of infection after gynecologic procedures like hysterectomy or endometrial biopsy. Women who undergo these procedures are typically screened and treated beforehand to prevent complications.
How Is BV Diagnosed?
Diagnosis requires a medical evaluation. A healthcare provider will perform a pelvic exam and collect a sample of vaginal discharge. The sample is examined under a microscope to look for clue cells, which are vaginal epithelial cells covered with bacteria.
Three of the following four criteria must be present for a clinical diagnosis:
- Thin, homogeneous vaginal discharge
- Vaginal pH greater than 4.5
- Positive whiff test, where a fishy odor is released when potassium hydroxide is added to the discharge
- Clue cells visible on microscopic examination
Some clinics use nucleic acid amplification tests (NAAT) that detect bacterial DNA. These are highly sensitive and can identify BV even when symptoms are mild or absent. At-home test kits exist, but they only measure pH and cannot confirm BV. A positive pH test does not mean you have BV, as other conditions like trichomoniasis also raise vaginal pH.
What Are the Treatment Options for BV?
BV is treated with prescription antibiotics. The two primary medications are metronidazole and clindamycin. Both are highly effective, with cure rates around 80% within one month of treatment.
Metronidazole is available as an oral tablet or a vaginal gel. Oral metronidazole is typically taken twice daily for seven days. The vaginal gel is used once daily for five days. Clindamycin is available as a vaginal cream used once daily for seven days.
Tinidazole is an alternative oral medication. It is equally effective but generally more expensive. All of these medications require a prescription from a healthcare provider.
Alcohol must be strictly avoided while taking oral metronidazole and for 48 hours after the last dose. Combining the drug with alcohol causes severe nausea, vomiting, and abdominal cramping. Clindamycin cream is oil-based and can weaken latex condoms and diaphragms for up to 72 hours after use.
Recurrence is common. About 30% of women experience a return of symptoms within three months, and up to 50% relapse within six months to a year. The reasons for recurrence are not fully clear, but it likely relates to the persistence of biofilms, protective communities of bacteria that resist antibiotic penetration.
Can BV Be Prevented?
No guaranteed prevention strategy exists, but several habits are associated with lower risk.
Avoid douching completely. This is the single most important preventive measure. The vagina is self-cleaning and does not require internal washing.
Use condoms consistently during sexual activity. Condoms reduce the introduction of new bacteria into the vaginal environment and lower the risk of BV by roughly 40% in some studies.
Limit the number of sexual partners. A new partner, or a partner who has had other partners recently, increases the chance of bacterial shifts. Some research suggests that using a condom with a new partner for the entire first year of the relationship significantly reduces BV risk.
Wear cotton underwear and avoid tight-fitting synthetic clothing. This keeps the genital area dry and prevents moisture buildup, though the direct link to BV prevention is not strongly established in clinical trials.
Probiotics containing Lactobacillus strains are widely marketed for vaginal health. The evidence is mixed. Some studies suggest oral or vaginal probiotics may help restore normal flora after antibiotic treatment, but no specific product, strain, or dosing regimen has been proven effective in large clinical trials. Do not rely on probiotics alone to treat an active infection.
When Should You See a Healthcare Provider?
See a provider if you notice any change in vaginal discharge, especially if it has a fishy odor. Seek care promptly if you are pregnant and suspect you have BV, because of the associated pregnancy risks.
You should also seek medical attention if you experience pelvic pain, fever, or pain during intercourse. These symptoms may indicate that the infection has spread to the upper reproductive tract, which requires different treatment.
BV does not resolve on its own in most cases. Without treatment, the bacterial imbalance tends to persist or worsen. Over-the-counter yeast infection medications will not help BV and may delay proper treatment. Only a healthcare provider can distinguish between these conditions and prescribe the correct antibiotic.
Frequently Asked Questions
Can BV go away on its own without treatment?
In rare cases, mild BV resolves without treatment, but most infections persist or worsen without antibiotics. Untreated BV also carries risks of complications like pelvic inflammatory disease and increased susceptibility to STIs.
Is bacterial vaginosis a sexually transmitted infection?
No, BV is not classified as an STI, though sexual activity is a risk factor. It is a bacterial imbalance that can occur in sexually inactive women and even in those who have never had intercourse.
Can men get bacterial vaginosis?
Men do not develop BV because the condition requires the vaginal environment. The bacteria associated with BV can colonize the male urethra, but treating male partners does not reduce recurrence rates in women, so partner treatment is not recommended.
Does BV cause infertility?
BV does not directly cause infertility, but it increases the risk of pelvic inflammatory disease, which can damage the fallopian tubes and lead to infertility. Prompt treatment of BV reduces this risk.
