What is bacterial vaginosis?

Bacterial vaginosis, or BV, is an infection of the vagina that’s often characterized by itchiness and excessive discharge. Although it’s one of the most common vaginal infections, researchers don’t yet know how it’s spread. It generally affects women of childbearing age, but it’s also been found in infants, children with no exposure to sex, and postmenopausal women.

Researchers used to think that BV was fairly harmless. But they’ve recently found that if untreated, it can put you at risk of more serious disorders such as pelvic inflammatory disease, an infection of the Fallopian tubes that can lead to permanent tissue scarring and infertility. Bacterial vaginosis has also been linked to an infection of the uterus called endometritis, and health problems following invasive procedures, including the placement of an IUD, according to the Centers for Disease Control and Prevention (CDC).

On top of that, BV can cause complications during pregnancy. According to the CDC, pregnant women with BV are more likely to go into preterm labor and give birth prematurely than those without BV. Research has also linked the condition to infection of the amniotic fluid (the liquid surrounding a fetus in the womb), as well as infections following a caesarean section.

What are the symptoms?

Fifty percent of women with BV have no symptoms at all. If you do, you’ll probably notice a white or grayish vaginal discharge, itchiness, redness, and an unpleasant fishy odor. Researchers think the odor is more marked during menstruation and following sexual intercourse.
The symptoms are caused by a variety of bacteria including Gardnerella vaginalis. Like many other vaginal infections, BV is thought to reduce the number of health-promoting lactobacilli bacteria in the vagina, a loss that can lead to the proliferation of bad bacteria.

How would I get it?

Again, the experts aren’t sure. Some research indicates that there’s a link with sexual activity, but there is no definitive evidence that it’s spread through sex. Risk factors include a new sex partner or having multiple sex partners. Women who have never had sex rarely get BV however treating male sex partners has not prevented its recurrence. Newborns can get BV if their mothers are infected with it, so if you’re planning to get pregnant, you should get tested for the infection. BV is also linked to douching and a lack of certain “good” bacteria (lactobacilli) in the vagina, according to the CDC.

How is it diagnosed?

BV is diagnosed by using clinical or Gram-stain tests, according to the CDC. The clinical procedure consists of four steps, three of which must yield a positive result to confirm a diagnosis of BV.

  • First your doctor or a nurse takes a sample of your vaginal fluid. Magnified under a microscope, it may show the presence of numerous cells containing BV bacteria.
  • Next the vaginal fluid is analyzed. If a thin, white discharge coats the vaginal walls, BV may be present.
  • A lab then checks the fluid to determine whether it’s normally acidic, with a pH ranging from approximately 3.9 to about 4.2. If the pH is greater than 4.5, you may have BV.
  • A technician adds an alkaline solution to the vaginal fluid and does a whiff test. A fishy odor indicates that BV is in the picture.

The CDC cautions doctors against diagnosing BV by simply taking a culture of the bacterium G. vaginalis, because it’s not specific enough to show whether you have the infection.

What are my treatment options?

For some time BV has been treated successfully with metronidazole, an antibiotic in pill form. The recommended treatment is a pill containing 500 milligrams of metronidazole, taken twice a day for 7 days, or metronidazole gel (0.75 percent), applied to the vagina with an applicator once a day for 5 days, according to 2006 guidelines from the CDC. The agency also recommends treating BV with clindamycin, used as a vaginal cream (2 percent) at bedtime once a day for 7 days.

Note: Because clindamycin can damage latex products such as diaphragms and condoms, you may want to wait to have intercourse until you’ve finished the treatment. In addition, you shouldn’t drink alcohol while you’re being treated with metronidazole or for 24 hours afterwards.

All women who are pregnant and have the symptoms of BV should get treated for it. However, many women have BV and don’t know it. For this reason, and since BV is associated with premature birth and other serious medical complications during pregnancy, women at high risk of giving birth early should receive treatment for BV, even if they don’t have symptoms. If you are pregnant and have BV, or suspect you have it, discuss testing and treatment options with your doctor.

How can I avoid getting BV?

Scientists do not completely understand BV so one knows for sure how to prevent it. However, research does show that BV is associated with having a new or more than one sex partner. Below are some basic steps to help reduce the risk of upsetting the natural balance of bacteria in the vagina and developing BV:

  • Because the “good” lactobacilli bacteria help control the growth of harmful bacteria and infection, get the nutrients you need to keep them happy. Eating yogurt that contains active acidophilus (you’ll find it at health food stores) helps maintain the health of your vagina (although there’s no evidence it helps in the treatment of BV).
  • Limit your number of sex partners.
  • Avoid vaginal douching, since it decreases the number of good lactobacilli in the vagina.
  • Since an IUD may increase your chances of getting BV, consider another form of birth control if you have recurring infections.


McGregor JA, et al. Bacterial vaginosis in pregnancy. Obstet Gynecol Surv 2000 May;55(5 Suppl 1):S1-19.

Calzolari E, et al. Bacterial vaginosis and contraceptive methods. Int J Gynaecol Obstet 2000 Sep;70(3):341-6.

Hillier SL, et al. Association between bacterial vaginosis and preterm delivery of a low-birth-weight infant. The Vaginal Infections and Prematurity Study Group. N Engl J Med 1995 Dec 28;333(26):1737-42.

Hitti J, et al. Vaginal indicators of amniotic fluid infection in preterm labor. Obstet Gynecol 2001 Feb;97(2):211-9.

Sexually Transmitted Diseases Treatment Guidelines 2002, Centers for Disease Control and Prevention. Morbidity and Mortality Weekly Report, May 10, 2002, Vol. 51, No. RR-6.

Merck Manuals. Puerperal Endometritis. November 2008.

Centers for Disease Control. Sexually Transmitted Diseases Treatment Guidelines.

Centers for Disease Control. Bacterial Vaginosis. February 2008.

© HealthDay

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