Discusses common vaginal infection. Covers symptoms like vaginal discharge and odor. Covers possible complications, including miscarriage, premature birth, and pelvic inflammatory disease. Looks at treatment with antibiotics. Offers prevention tips.
What is bacterial vaginosis?
is a mild infection of the
vagina caused by bacteria. Normally, there are a lot
of "good" bacteria and some "bad" bacteria in the vagina. The good types help
control the growth of the bad types. In women with bacterial vaginosis, the
balance is upset. There are not enough good bacteria and too many bad
Bacterial vaginosis is usually a mild problem that may
go away on its own in a few days. But it can lead to more serious problems. So
it's a good idea to see your doctor and get treatment.
What causes bacterial vaginosis?
Experts are not
sure what causes the bacteria in the vagina to get out of balance. But certain
things make it more likely to happen. Your risk of getting bacterial vaginosis
is higher if you:
more than one sex partner or have a new sex partner.
You may be able to avoid bacterial vaginosis if you limit
your number of sex partners and don't douche or smoke.
vaginosis is more common in women who are sexually active. But it can occur if you are not sexually active as well.
What are the symptoms?
The most common symptom is
a smelly vaginal discharge. It may look grayish white or yellow. A sign of
bacterial vaginosis can be a "fishy" smell, which may be worse after sex. About
half of women who have bacterial vaginosis do not notice any symptoms.
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
What problems can bacterial vaginosis cause?
Bacterial vaginosis usually does not 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
If you have it and you are exposed to a sexually
transmitted infection (including
HIV), you are more likely to catch the infection.
How is it treated?
Doctors usually prescribe an
antibiotic to treat bacterial vaginosis. They come as pills you swallow or
as a cream or capsules (called ovules) that you put in your vagina. If you are
pregnant, you will need to take pills.
usually clears up in 2 or 3 days with antibiotics, but treatment goes on for 7
days. Do not stop using your medicine just because your symptoms are better. Be sure to take the full course of antibiotics.
Antibiotics usually work well and have few side effects.
But taking them can lead to a
vaginal yeast infection. A yeast infection can cause
itching, redness, and a lumpy, white discharge. If you have these symptoms,
talk to your doctor about what to do.
Bacterial vaginosis is caused by an imbalance of the organisms (flora) that
naturally exist in the
vagina. Normally, about 95% of vaginal flora are
lactobacillus bacteria. (These types are unique to humans, different from the
lactobacillus in yogurt.) These lactobacilli help keep the vaginal
pH level low and prevent overgrowth of other types of
organisms. Women with bacterial vaginosis have fewer lactobacillus organisms
than normal and more of other types of bacteria. Experts do not yet understand what causes this imbalance.
specific cause isn't known, a number of health and lifestyle factors have been
linked to bacterial vaginosis. For more information, see What Increases
Many women with bacterial vaginosis do not have any symptoms. Bacterial vaginosis does not typically cause itching. But it
An excessive grayish white vaginal discharge,
unlike normal vaginal discharge. Some women describe the discharge as "yellow."
"fishy" odor, which is usually worse after sex (intercourse).
Bacterial vaginosis often clears up on its own. But in
some women it doesn't go away on its own. And for many women it comes back
after it has cleared up. Antibiotic treatment works for some women but not
Your risk of complications from
bacterial vaginosis is higher:
Compared to pregnant women who don't have it, women who have
bacterial vaginosis during pregnancy have a higher
risk of early (preterm) delivery or of uterine infection after pregnancy. Also,
pregnant women may have an increased risk of
After gynecological surgery. Women with
bacterial vaginosis at the time of an invasive vaginal procedure have an
increased risk of developing more serious infection or inflammation, such as
pelvic inflammatory disease (PID) or
When exposed to HIV or other sexually transmitted infection. Women who have bacterial vaginosis when they are
sexually transmitted infections (including
HIV) have an increased risk of becoming infected with
the sexually transmitted infection.
What Increases Your Risk
Things that increase your
risk of getting
bacterial vaginosis include:
more than one sex partner or having a new sex partner.
Not using condoms.
Although bacterial vaginosis can be triggered by or get
worse from sexual activity, it does not appear to be an infection that is
passed from man to woman. So experts do not consider bacterial
vaginosis to be a male-female sexually transmitted infection. Bacterial vaginosis may be passed from woman to woman during sexual contact.
When To Call a Doctor
Bacterial vaginosis can be hard to distinguish from other types of vaginal
infection. Consider the following if you have any signs of vaginal
Call your doctor immediately if
Develop lower belly pain and a fever higher
than 101°F (38.3°C) along with
a vaginal discharge.
pregnant and have symptoms of a vaginal
Call your doctor for an appointment within 1 week if
Have vaginal discharge with an unusual or foul odor.
Have pain during sex or during
Develop any other discomfort or discharge that may
mean you have a vaginal infection.
If you have not been diagnosed with bacterial vaginosis but
you have symptoms that concern you, see:
It's generally recommended that you contact or
see your doctor about unusual vaginal symptoms.
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
Who to see
Doctors who can diagnose and treat bacterial vaginosis
Wet mount. A sample of vaginal discharge is mixed
with a salt (normal saline) solution after placing it on a
microscope slide. The prepared slide is examined to identify the bacteria
present, to look for
white blood cells that point to an infection, and to
look for unusual cells called clue cells. The presence of clue cells is one sign f bacterial vaginosis.
Whiff test. Several drops of a potassium hydroxide
(KOH) solution are added to a sample of vaginal discharge to find out whether
a strong fishy odor is produced. A fishy odor on the whiff test suggests
Vaginal pH. The normal vaginal
pH is 3.8 to 4.5. Bacterial vaginosis usually causes
the vaginal pH to rise above 4.5.
Oligonucleotide probes. This test detects the
genetic material (DNA) of bacterial vaginosis bacteria.
Oligonucleotide probe testing is very accurate but is not routinely available
in most labs.
The presence of clue cells, an increased vaginal pH,
and a positive whiff test are enough evidence to treat for bacterial vaginosis.
Bacterial vaginosis may be found during a routine pelvic exam.
bacterial vaginosis includes antibiotic medicine (oral or vaginal). Antibiotics kill the problem bacteria causing bacterial vaginosis symptoms. But symptoms can come back after antibiotic treatment.
For some women, bacterial vaginosis goes away without
treatment. But when it does not go away even with treatment, bacterial
vaginosis is frustrating and troublesome. Bacterial vaginosis makes the reproductive tract vulnerable
to infection or inflammation. So your doctor will test and treat you with antibiotics for
bacterial vaginosis if you are:
Having persistent symptoms.
Pregnant and have symptoms.
Planning to have a
hysterectomy or surgical abortion. Treating bacterial
vaginosis with antibiotics beforehand may lower your risk of getting a
serious infection afterward.
Talk to your doctor about whether testing is right for
What to think about
doctor finds other problems during the exam, such as a possible sexually transmitted infection (STI), appropriate
treatment will be recommended.
To help prevent
Limit the number of sex partners you have.
Use condoms consistently.
Bacterial vaginosis may be passed between women during
sexual contact. If you have a female sex partner, you may benefit from using
protection and carefully washing shared sex toys.
Bacterial vaginosis is generally not considered a
sexually transmitted infection (STI). But if you are
exposed to an STI while you have bacterial vaginosis, you are more likely to get that infection.
It is always
practice safer sex to prevent sexually transmitted infections, whether or not you have bacterial vaginosis. Preventing an STI is easier than treating an infection after it occurs.
Some women have used
Lactobacillus acidophilus in yogurt or supplements to
bacterial vaginosis. But dairy lactobacillus does not
work for bacterial vaginosis. This is because dairy lactobacillus is not the
kind of bacteria that normally live in the vagina.
More research is needed to find out if the types of lactobacillus normally found in a healthy vagina may work to treat bacterial vaginosis.
antibiotics metronidazole (such as Flagyl and MetroGel),
clindamycin (such as Cleocin and Clindesse), and tinidazole (such as Tindamax) are used to
bacterial vaginosis. Depending on the antibiotic you
are prescribed, you may take it by mouth or use it vaginally.
During pregnancy, women are usually prescribed oral medicine.
treatment for bacterial vaginosis, ask your doctor whether you should:
Use oral medicine or medicine inserted into the
vagina. Some women prefer to take pills rather than using a vaginal
Avoid having sex during the time that you are being
Continue treatment during your menstrual period. Medicine
placed in your vagina is harder to use during your period, but your
doctor may recommend continuing treatment during this time.
drinking alcohol during treatment with metronidazole or tinidazole. These
medicines can cause severe nausea and vomiting if you drink alcohol when you
are taking one of them. Clindamycin does not.
The oil in clindamycin cream and ovules can weaken latex. This means condoms and diaphragms may break, and you may not be protected from STIs or pregnancy.
Other Places To Get Help
American Congress of Obstetricians and Gynecologists
Abramowicz M (2010). Drugs for sexually transmitted infections. Treatment Guidelines From The Medical Letter, 8(95): 53–60.
American College of Obstetricians and Gynecologists
(2006, reaffirmed 2011). Vaginitis. ACOG Practice Bulletin No. 72. Obstetrics and Gynecology, 107(5): 1195–1206.
Bornstein J (2013). Benign disorders of the vulva and vagina. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 620–645. New York: McGraw-Hill.
Eckert LO, Lentz GM (2012). Infections of the lower and upper genital tracts: Vulva, vagina, cervix, toxic shock syndromes, endometriosis, and salpingitis. In GM Lentz et al., eds., Comprehensive Gynecology, 6th ed., pp. 519–559. Philadelphia: Mosby.
Mackay G (2013). Sexually transmitted diseases and pelvic infections. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 701–731. New York: McGraw-Hill.
Marrazzo J, Sobel J (2010). Vaginal infections. In SA Morse et al., eds., Atlas of Sexually Transmitted Diseases and AIDS, 4th ed., pp. 76–85. Philadelphia: Saunders.
Soper DE (2012). Genitourinary infections and sexually transmitted diseases. In JS Berek, ed., Berek and Novak's Gynecology, 15th ed., pp. 557–573. Philadelphia: Lippincott Williams and Wilkins.
How this information was developed to help you make better health decisions.