Bacterial vaginosis is the
most common type of vaginal infection. To learn more about other common types,
see the topics
Vaginal Yeast Infections and
Trichomoniasis.
What is bacterial vaginosis?
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
bacteria.
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:
Have more than one sex partner.
Have a female sex
partner.
Smoke.
Douche.
You may be able to avoid bacterial vaginosis if you limit
your number of sex partners and don't douche or smoke.
Bacterial
vaginosis is more common in women who are sexually active, but it is probably
not something you catch from another person.
What are the symptoms?
The most common symptom is
a smelly vaginal discharge. It may look grayish white or yellow. A sure sign of
bacterial vaginosis is a "fishy" smell, which may be worse after sex. About
half of women who have bacterial vaginosis do not notice any symptoms.
Many things can cause abnormal vaginal discharge, including some sexually
transmitted diseases (STDs). See your doctor so you can be tested and get the
right treatment.
How is bacterial vaginosis 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.
What problems can bacterial vaginosis cause?
Bacterial vaginosis usually does not cause other health problems. But it
can lead to serious problems in some cases.
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
C-section, abortion, or
hysterectomy, you are more likely to get a pelvic
infection.
If you have it and you are exposed to a sexually
transmitted disease (including
HIV), you are more likely to catch the disease.
Getting treated with antibiotics can help prevent these
problems.
How is it treated?
Doctors usually prescribe an
antibiotic to treat bacterial vaginosis. The ones used
most often are metronidazole and clindamycin. 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.
Bacterial vaginosis
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. It
is important to take the full course of antibiotics.
If you are
treated with antibiotics:
Avoid all alcohol use, including
over-the-counter medicines that contain alcohol (such
as NyQuil), if you are taking metronidazole or tinidazole. Mixing alcohol and
metronidazole, or alcohol and tinidazole, can cause severe nausea and
vomiting.
Don't trust condoms or diaphragms if you use clindamycin
creams or ovules. These treatments have an oil that can weaken latex. This can
cause condoms and diaphragms to fail.
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.1
Although the
specific cause isn't known, a number of health and lifestyle factors have been
linked to bacterial vaginosis. For more information, see the What Increases
Your Risk section of this topic.
About half of women with
bacterial vaginosis have no telltale symptoms.2 Bacterial vaginosis does not typically cause itching. But it
does cause:
An excessive grayish white vaginal discharge,
unlike normal vaginal discharge (1 in 3 women with bacterial vaginosis describe
the discharge as yellow).3
A bothersome
"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
others.
About 1 out of 4 women find that bacterial
vaginosis clears up without medicine after a week.1
Bacterial vaginosis recurs in about 1 out of 3
treated women.2
Complications
Your risk of complications from
bacterial vaginosis is higher:
During pregnancy.
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 uterine infection after pregnancy. Also,
pregnant women may have an increased risk of
miscarriage.
When exposed to HIV or other sexually transmitted diseases. Women who have bacterial vaginosis when they are
exposed to
sexually transmitted diseases (including
HIV) have an increased risk of becoming infected with
the sexually transmitted disease.1
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. Therefore, experts do not consider bacterial
vaginosis to be a male-female sexually transmitted disease. It is possible but
not proven that bacterial vaginosis is passed from woman to woman during sexual
contact.
Bacterial vaginosis can be difficult to distinguish from other types of vaginal
infection. Consider the following if you have any signs of vaginal
infection.
Call your doctor immediately if
you:
Develop lower abdominal pain and a fever higher
than 101°F (38.33°C) along with
a vaginal discharge.
Are
pregnant and have symptoms of a vaginal
infection.
Call your doctor for an appointment within 1 week if
you:
Develop an unusual vaginal discharge that has a
foul odor, especially noticeable after sex.
Have unusual vaginal
itching.
Have pain during sex or during
urination.
Develop any other discomfort or discharge that may
indicate a vaginal infection.
If you have not been diagnosed with bacterial vaginosis but
you have symptoms that cause you concern, see the following topics:
It's generally recommended that you contact or
see your doctor about vaginal symptoms. The only exception to this rule is when
you are sure that your vaginal symptoms indicate a
vaginal yeast infection. If you have had a yeast
infection before and are sure that your problem is a yeast infection rather
than bacterial vaginosis, you can consider home treatment with a
nonprescription product to treat yeast infections. For more information, see
the topic
Vaginal Yeast Infections.
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 indicate an infection, and to
look for unusual cells called clue cells. The presence of clue cells is the
most reliable indicator of bacterial vaginosis.
Whiff test. Several drops of a potassium hydroxide
(KOH) solution are added to a sample of vaginal discharge to determine whether
a strong fishy odor is produced. A fishy odor on the whiff test suggests
bacterial vaginosis.
Vaginal pH. The normal vaginal
pH is 3.8 to 4.5. Bacterial vaginosis usually causes
the vaginal pH to rise above 4.5.
Gram stain. A sample of the vaginal discharge is
placed on a microscope slide. A special dye is applied to the slide, causing
certain types of bacteria (Gram-positive bacteria) to turn a shade of purple
while coloring others (Gram-negative bacteria) pink. In bacterial vaginosis,
Gram-negative bacteria, especially Gardnerella vaginalis, are most common.
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 detected during routine
Pap testing. But Pap testing is not a standard test to
diagnose bacterial vaginosis.
Watchful waiting. In about 1 out of 4 women, bacterial vaginosis symptoms resolve
on their own.1 This happens when the vaginal
lactobacilli organisms increase to their normal levels, and other bacteria
levels drop.
Antibiotic medicine (oral or vaginal).
Antibiotics can kill the problem bacteria causing bacterial vaginosis symptoms
but sometimes don't reverse the underlying cause. Therefore, symptoms recur in
about 1 out of 3 of women after antibiotic treatment.2
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. And, it can lead to preterm labor if
you have it during pregnancy. If present during pelvic surgery or invasive
vaginal procedures, bacterial vaginosis makes the reproductive tract vulnerable
to infection or inflammation, which has been linked to such problems as
pelvic inflammatory disease (PID).4 So your doctor will test and treat you with antibiotics for
bacterial vaginosis if you are:
Pregnant with
no symptoms, but have a history of preterm labor (before 37 completed weeks of
pregnancy) that may have been related to infection.6
Planning to have a
hysterectomy or surgical abortion. Treating bacterial
vaginosis with antibiotics beforehand greatly lowers your risk of getting a
serious infection afterward. Other procedures linked to bacterial
vaginosis-related infection include
endometrial biopsy,
intrauterine device (IUD) placement,
cesarean section,
dilation and curettage (D&C), and
hysterosalpingography, an X-ray test that examines the
inside of the uterus, the fallopian tubes, and surrounding area.4
Talk to your doctor about whether screening is right for
you.
What To Think About
If you are planning to become
pregnant and have symptoms or a history of bacterial vaginosis, talk to your
doctor about screening and treatment before you start a pregnancy.
Women should not breast-feed while taking tinidazole or for 3 days after
they are finished taking this medicine.
For decades, some women
have used Lactobacillus acidophilus in yogurt or
supplements to treat bacterial vaginosis. But experts now know that dairy
lactobacillus is not the kind that normally lives in the vagina. This is why
dairy lactobacillus does not work for bacterial vaginosis. But researchers have
found that two different types of lactobacillus—L. crispatus and L. jensenii—are most commonly found
in a healthy vaginal environment. Research is now focusing on using these types
of lactobacilli in capsules.7
If your
doctor finds other problems during the exam, such as a possible
sexually transmitted disease (STD), appropriate
treatment will be recommended.
Since it probably is not passed
between a man and woman, treating a male sex partner or partners will not help
cure bacterial vaginosis.4 But for a woman with a
female sex partner, it is possible that bacterial vaginosis is passed back and
forth, although this is not yet proven. In this case, treating both partners
may help.
Limit the number of sex partners you have.
Multiple sex partners increase your risk of getting bacterial vaginosis by
changing the normal environment of the vagina.
Avoid
douching.
Bacterial vaginosis may be passed between women during
sexual contact. If you have a female sexual partner, you may benefit from using
condoms with or careful washing of shared sex items.8
Bacterial vaginosis is not passed between men
and women and is not considered a
sexually transmitted disease (STD). But if you are
exposed to an STD while you have bacterial vaginosis, you are more likely to be
infected by that disease.1
For decades, some women have used
Lactobacillus acidophilus in yogurt or supplements to
treat
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.8
Researchers are studying the two different
types of lactobacillus—L. crispatus and L. jensenii—that are most commonly found in a healthy
vagina.7 These lactobacilli may prove to be an
effective treatment for bacterial vaginosis.
The
antibiotics metronidazole (such as Flagyl, MetroGel),
clindamycin (such as Cleocin, Clindesse), and tinidazole (Tindamax) are used to
treat
bacterial vaginosis. Depending on the antibiotic you
are prescribed, you may take it by mouth or use it vaginally.
During pregnancy, women who are high-risk for preterm labor are advised
to avoid vaginal application of any treatment. Some doctors recommend that all
pregnant women avoid vaginal treatments.
Studies generally show
that vaginal antibiotics are as effective as oral antibiotics for treating
bacterial vaginosis.9 Medicines inserted into the
vagina cause fewer side effects than oral medicines, although they can make you
vulnerable to
vaginal yeast infection.
When considering
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
medicine.
Avoid having sex during the time that you are being
treated.
Continue treatment during your menstrual period. Medicine
placed in your vagina is more difficult to use during your period, but your
doctor may recommend continuing treatment during this time.
Avoid
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 mineral oil in clindamycin cream or ovules can cause
latex condoms or diaphragms to fail. This is also true for metronidazole cream
and tablets (the gel is fine for use with condoms and diaphragms).
Don't trust barrier methods of birth control when using this type of vaginal medicine.
For decades, some women have
used Lactobacillus acidophilus in yogurt or supplements
to treat
bacterial vaginosis. But researchers now know that
dairy lactobacillus does not work for bacterial vaginosis. This is because
dairy lactobacillus is not the kind of bacteria that normally lives in the
vagina. Researchers have found two different types of lactobacillus—L. crispatus and L. jensenii—that are most commonly
found in a healthy vaginal environment. Research is now focusing on using these
types of lactobacilli in capsules.7
The American Academy of Family Physicians produces a
variety of health-related educational materials. Its Web site offers a health
library and bulletin board, news, and comments sections.
American College of Obstetricians and Gynecologists
(ACOG)
409 12th Street SW
P.O. Box 96920
Washington, DC 20090-6920
Phone:
(202) 638-5577
E-mail:
resources@acog.org
Web Address:
www.acog.org
American College of Obstetricians and Gynecologists
(ACOG) is a nonprofit organization of professionals who provide health care for
women, including teens. The ACOG Resource Center publishes manuals and patient
education materials. The Web publications section of the site has patient
education pamphlets on many women's health topics, including reproductive
health, breast-feeding, violence, and quitting smoking.
Centers for Disease Control and Prevention
(CDC)
1600 Clifton Road
Atlanta, GA 30333
Phone:
1-800-CDC-INFO (1-800-232-4636)
TDD:
1-888-232-6348
E-mail:
cdcinfo@cdc.gov
Web Address:
www.cdc.gov
The Centers for Disease Control and Prevention (CDC) is
an agency of the U.S. Department of Health and Human Services. The CDC works
with state and local health officials and the public to achieve better health
for all people. The CDC creates the expertise, information, and tools that
people and communities need to protect their health—by promoting health,
preventing disease, injury, and disability, and being prepared for new health
threats.
Koumans EH, et al (2002). Indications for therapy and
treatment recommendations for bacterial vaginosis in nonpregnant and pregnant
women: A synthesis of data. Clinical Infectious Diseases, 35(Suppl 2): S152–S172.
Joesoef MR, Schmid G (2005). Bacterial vaginosis,
search date March 2004. Online version of BMJ Clinical Evidence. Also available online:
http://www.clinicalevidence.com.
Hillier S, et al. (2008). Bacterial vaginosis. In KK
Holmes et al., eds., Sexually Transmitted Diseases, 4th
ed., pp. 737–768. New York: McGraw-Hill.
Centers for Disease Control and Prevention (2002).
Diseases characterized by vaginal discharge section of Sexually transmitted
diseases treatment guidelines. MMWR, 51(RR-6): 42–48.
Fethers K, et al. (2000). Sexually transmitted
infections and risk behaviours in women who have sex with women.
Sexually Transmitted Infections, 76(5):
345–349.
U.S. Preventive Services Task Force (2008). Screening
for bacterial vaginosis in pregnancy to prevent preterm delivery: U.S.
Preventive Services Task Force recommendation statement. Annals of Internal Medicine, 148(3): 214–220.
Kessel KV, et al. (2003). Common complementary and
alternative therapies for yeast vaginitis and bacterial vaginosis: A systematic
review. Obstetrical and Gynecological Survey, 58(5):
351–358.
Marrazzo JM (2004). Evolving issues in understanding
and treating bacterial vaginosis. Expert Review of Anti-Infective Therapy, 2(6): 913–922.
Leitich H, et al. (2003). Antibiotic treatment of
bacterial vaginosis in pregnancy: A meta-analysis. American Journal of Obstetrics and Gynecology, 188(3): 752–758.
Other Works Consulted
Abramowicz M (2007). Tinidazole (Tindamaz)—A new
option for treatment of bacterial vaginosis. Medical Letter on Drugs and Therapeutics, 49(1269): 73–74.
Abramowicz M (2007). Treatment guidelines: Drugs for
sexually transmitted infections. Medical Letter on Drugs and Therapeutics, 5(61): 81–88.
Ainbinder SW, et al. (2007). Sexually transmitted
diseases and pelvic infections. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology,
10th ed., p. 670. New York: McGraw-Hill.
Mazdisnian F (2007). Benign disorders to the vulva
and vagina. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 10th ed., pp. 598–622. New York:
McGraw-Hill.
American College of Obstetricians and Gynecologists
(2006). Vaginitis. ACOG Practice Bulletin No. 72. Obstetrics and Gynecology, 107(5): 1195–1206.
Eckert LO, Lentz GM (2007). Infections of the lower
genital tract. In VL Katz et al., eds., Comprehensive Gynecology, 5th ed., pp. 569–606. Philadelphia: Mosby
Elsevier.
Soper DE (2007). Genitourinary infections and sexually
transmitted diseases. In JS Berek, ed., Novak's Gynecology, 14th ed., pp. 541–559. Philadelphia: Lippincott Williams and
Wilkins.
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