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Bacterial vaginosis (BV) is an infection in the vagina caused by bacteria. The vagina naturally has "good" bacteria called lactobacilli and a few "bad" bacteria called anaerobes. Normally, there’s a careful balance between lactobacilli and anaerobes. When that balance is disrupted, however, anaerobes can increase in number and cause BV.
BV is the most common vaginal infection in women between ages 15 and 44. It’s also one of the most common infections in women who are pregnant, affecting approximately 1 million pregnant women each year. BV is typically a mild infection and is easily treatable with medication. When left untreated, however, the infection can increase your risk for sexually transmitted infections and complications during pregnancy.
Approximately 50 to 75 percent of women with BV don’t experience any symptoms. When symptoms do occur, you may have abnormal and foul-smelling vaginal discharge. The discharge is usually thin and dull gray or white. In some cases, it may also be foamy. The fish-like odor that’s often associated with the discharge is a result of the chemicals that are produced by the bacteria that cause BV. Menstruation and sexual intercourse usually make the odor worse, as blood and semen react with the bacteria to release odorous chemicals. Itching or irritation around the outside of the vagina can also occur in women with BV.
BV is the result of an overgrowth of certain bacteria in the vagina. Like in other parts of the body, including the mouth and intestines, there are various bacteria that live in the vagina. Many of these bacteria actually protect the body from other bacteria that can cause disease. In the vagina, lactobacilli are the naturally occurring bacteria that fight off infectious bacteria. The infectious bacteria are known as anaerobes.
There’s normally a natural balance between lactobacilli and anaerobes. Lactobacilli typically account for the majority of bacteria in the vagina and control the growth of anaerobes. However, if the lactobacilli are reduced in number, anaerobes have the opportunity to grow. When an overgrowth of anaerobes takes place in the vagina, BV can occur.
Doctors don’t know the exact cause of the bacterial imbalance that triggers BV. However, certain factors can increase your risk of developing the infection. These include:
To diagnose BV, your doctor will ask you about your medical history and perform a pelvic exam. During the exam, your doctor will examine your vagina and check for signs of an infection. Your doctor will also take a sample of your vaginal discharge so it can be analyzed under a microscope.
BV is often treated with antibiotics. These may come as pills you swallow or as a cream that you insert into your vagina. Regardless of the type of treatment used, it’s important to follow your doctor’s instructions and to complete the full round of medication.
Your doctor may prescribe the following antibiotics:
These medications are usually effective in treating BV. They all have similar side effects, with the exception of metronidazole. This particular medication may cause severe nausea, vomiting, and headaches when taken with alcohol. Make sure to speak with your doctor if you have concerns about any of the possible side effects.
Once treatment is received, BV usually clears up within two to three days. However, treatment usually continues for at least one week. Don’t stop taking your medications until your doctor tells you to do so. It’s important to take the full course of antibiotics to prevent the infection from coming back. You may need long-term treatment if your symptoms persist or continue to come back.
When left untreated, BV can cause serious complications and health risks. These include:
You can take the following steps to lower your risk of developing BV:
BV is a common infection, but taking these preventive measures can reduce your risk of getting it. It’s crucial to call your doctor right away if you believe you have BV, especially if you’re pregnant. Getting prompt treatment will help prevent complications from occurring.
Written by: The Healthline Editorial Team
Medically reviewed on: Dec 24, 2015: Janine Kelbach, RNC-OB
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