Women’s Health Library
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What is bacterial vaginosis?
Bacterial vaginosis is a condition in which there is an overgrowth of certain bacteria that normally live in the vagina. It's usually a mild problem that may go away on its own. But it can lead to more serious problems. So it's a good idea to see your doctor and get treatment.
What causes it?
Bacterial vaginosis is caused by an overgrowth of bacteria that are normally in the vagina. No one knows exactly what causes the bacteria to overgrow. But certain things make it more likely to happen, such as douching or having a new sex partner.
What are the symptoms?
The most common symptom of bacterial vaginosis is abnormal vaginal discharge. It may look grayish white or yellow. It may have a "fishy" odor, which may be worse after vaginal intercourse. But in many cases, bacterial vaginosis doesn't cause any symptoms.
How is it diagnosed?
Doctors diagnose bacterial vaginosis by asking about the symptoms, doing a pelvic exam, and taking a sample of the vaginal discharge. The sample can be tested to find out if you have bacterial vaginosis.
How is bacterial vaginosis treated?
Treatment for bacterial vaginosis includes antibiotic medicine. Depending on the medicine prescribed, these may be taken either by mouth or in the vagina. Antibiotics kill the bacteria that cause symptoms. But symptoms often come back after antibiotic treatment.
It's normal for bacteria to be in the vagina. But when certain types of bacteria overgrow, it can cause bacterial vaginosis.
No one knows exactly what causes the bacteria to overgrow. But certain things make it more likely to happen. Your risk of getting bacterial vaginosis is higher if you:
- Have more than one sex partner or have a new sex partner.
- Have a sex partner with a vagina.
- Have another sexually transmitted infection (STI).
- Don't use condoms.
Bacterial vaginosis is more common if you are sexually active. But if you aren't having sex, you can also get it.
Here are some tips to help prevent bacterial vaginosis.
- Limit the number of sex partners you have.
- Avoid douching.
- Use condoms consistently.
- Practice good hygiene.
Wash your vulva daily with water or mild, unscented soap. Clean diaphragms, cervical caps, spermicide applicators, and sex toys after each use.
- Practice safer sex.
It is always important to practice safer sex to prevent sexually transmitted infections (STIs), whether or not you have bacterial vaginosis.
In many cases, bacterial vaginosis doesn't cause any symptoms. And it doesn't typically cause itching. But it may cause:
- Abnormal vaginal discharge. It may look grayish white or yellow. This is the most common symptom.
- A "fishy" odor. It may be worse after vaginal intercourse and during your period.
Bacterial vaginosis often clears up on its own. But in some cases it doesn't go away on its own. If your symptoms don't go away, treatment usually helps. But sometimes bacterial vaginosis comes back after it has cleared up.
Bacterial vaginosis usually doesn't cause other health problems. But in some cases it can lead to serious problems.
- If you have it when you are pregnant, it increases the risk of miscarriage, early (preterm) delivery, and uterine infection after pregnancy.
- If you have it when you have a pelvic procedure such as a cesarean section, an abortion, or a hysterectomy, you are more likely to get a pelvic infection.
- If you have it and you are exposed to a sexually transmitted infection (including HIV), you are more likely to catch the infection.
When to Call
Bacterial vaginosis can be hard to distinguish from other types of vaginal infection. Consider the following if you have any signs of vaginal infection.
Call your doctor now if you:
- Have pain in your lower belly and a fever higher than 101°F (38.3°C) along with a vaginal discharge.
- Are pregnant and have symptoms of a vaginal infection.
Call your doctor for an appointment if you:
- Have vaginal discharge with an unusual or foul odor.
- Have vaginal itching.
- Have pain during sex or during urination.
- Develop any other discomfort or discharge that may mean you have a vaginal infection.
It's a good idea to contact or see your doctor about unusual vaginal symptoms.
If your symptoms are due to a sexually transmitted infection (STI) and not bacterial vaginosis, you may infect a sex partner if you delay treatment. You may also develop more serious complications of STIs such as pelvic inflammatory disease (PID).
- To prevent the spread of a possible infection, avoid sex. Wait until after you have seen your doctor.
- Avoid douching.
Check your symptoms
Exams and Tests
Doctors diagnose bacterial vaginosis by asking about symptoms, doing a pelvic exam, and taking a sample of the vaginal discharge. The sample can be tested for bacterial vaginosis.
These lab tests may include:
- Wet mount.
A sample of discharge is checked for bacteria, white blood cells, and unusual cells called clue cells. These clue cells are one sign of bacterial vaginosis.
- Whiff test.
A special solution is added to a sample of discharge to see if it gives off a strong fishy odor. This odor usually means you have bacterial vaginosis.
- Vaginal pH.
The pH of a sample of vaginal discharge is measured. Bacterial vaginosis often causes a pH that is higher than normal.
- DNA test.
This test looks for the genetic material (DNA) of bacterial vaginosis bacteria.
The presence of clue cells, an increased vaginal pH, and a positive whiff test are enough evidence to treat for bacterial vaginosis.
Sometimes bacterial vaginosis goes away without treatment. But doctors usually prescribe an antibiotic medicine if you are having symptoms. Antibiotics kill the bacteria that cause symptoms. The medicine may be pills you swallow. Or it might be a cream or capsules that you put in your vagina. In many cases, symptoms come back after antibiotic treatment. If your symptoms come back, talk to your doctor.
Bacterial vaginosis makes the reproductive tract vulnerable to infection or inflammation. So if you are having symptoms of bacterial vaginosis, it is important to get tested and treated by your doctor.
- Take your antibiotics as directed. Do not stop taking them just because you feel better. You need to take the full course of antibiotics.
- Do not eat or drink anything that contains alcohol if you are taking metronidazole or tinidazole.
- Keep using your medicine if you start your period. Use pads instead of tampons while using a vaginal cream or suppository. Tampons can absorb the medicine.
- Wear loose cotton clothing. Do not wear nylon and other materials that hold body heat and moisture close to the skin.
- Do not scratch. Relieve itching with a cold pack or a cool bath.
- Do not wash your vulva more than once a day. Use plain water or a mild, unscented soap. Do not douche.
Can yogurt help?
Some people have tried treating bacterial vaginosis with the probiotic Lactobacillus. This is found in foods like yogurt and in dietary supplements. But more research is needed to find out if it works to treat or prevent bacterial vaginosis. It's also not clear which type of Lactobacillus would work best.
The antibiotics metronidazole (such as Flagyl and MetroGel), clindamycin (such as Cleocin and Clindesse), and tinidazole (such as Tindamax) are used to treat bacterial vaginosis. The medicine may be pills you swallow. Or it might be a cream or capsules that you put in your vagina.
You may be told by your doctor to avoid alcohol during treatment with metronidazole or tinidazole. These medicines can cause nausea and vomiting if you drink alcohol. And if you are being treated with Clindamycin cream or capsules, avoid using latex condoms during your treatment. The medicine may weaken latex. This means condoms and diaphragms may break and not protect you against sexually transmitted infections (STIs) or pregnancy.
Current as of: November 22, 2021
Author: Healthwise Staff
Sarah Marshall MD - Family Medicine
Kathleen Romito MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Devika Singh MD, MPH - Infectious Disease
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