Which treatments are effective in bacterial vaginosis?

The symptoms of bacterial vaginosis are usually treated with antibiotics such as clindamycin or metronidazole – in the form of a cream, vaginal suppositories or tablets, or oral tablets (to be swallowed). The treatment can last one to seven days depending on the exact drug used, its form, the dose, and the severity of the symptoms. You can talk to your doctor about what type of treatment is most suitable for you.

If you've been prescribed antibiotics, it's important to make sure you use them correctly. That especially means using the medicine regularly and for as long as prescribed: If you stop early – for instance, because the symptoms have already cleared up – resistant strains of bacteria are more likely to develop.

Clindamycin and metronidazole are very effective against vaginosis symptoms. Research on treatment with clindamycin creams has shown the following:

• Without clindamycin: 50% of the study participants who used a placebo (fake treatment) had no symptoms one to two weeks afterwards.
• With clindamycin: 88% of the study participants who used clindamycin had no symptoms one to two weeks after treatment.

Several studies have also shown that clindamycin and metronidazole are similarly effective: In the studies comparing these two antibiotics, over 90% of the women had no symptoms after treatment – regardless of which drug they had used.

Bacterial vaginosis can come back after a few weeks. That happens quite often: About half of all women have symptoms again about one year after the first infection. If you keep getting bacterial vaginosis, it may be a good idea to discuss the prevention options with your doctor.

Researchers have also looked into whether it's a good idea for your partner to take antibiotics too. But that wasn’t shown to speed up the recovery time or prevent the infection from coming back.

The antibiotics don’t only kill gardnerella bacteria. They also kill useful bacteria in the vagina that help to keep other germs in check. This means that treatment with antibiotics can sometimes end up causing a vaginal yeast infection (thrush). This happens in about 10% of women who use clindamycin or metronidazole. The typical symptoms of vaginal thrush include itching and a thick, white discharge. They can also be treated with medication.

Antibiotics occasionally have other side effects too. About 10% of women who take metronidazole tablets say that the tablets leave a metallic taste in their mouth. Less commonly, they cause nausea and vomiting. Clindamycin is very well tolerated when used as a cream, and has no known side effects apart from yeast infections (thrush).

Lactic acid bacteria are believed to help restore a healthy balance of germs in the vagina (healthy vaginal flora) and keep harmful bacteria in check. But there is less research on treatment with lactic acid bacteria than on treatment with antibiotics. Very few studies have looked at treatments with lactic acid bacteria on their own – they were usually used in combination with antibiotics. But there is currently no scientific proof that vaginosis clears up any better when using this combination. Little is known about the possible side effects of these medications.

If bacterial vaginosis develops during pregnancy, it can slightly increase the risk of the baby being born too early (preterm birth). There is also a higher risk of a late-term miscarriage or stillbirth (between week 13 and week 24 of pregnancy).

Researchers from the Cochrane Collaboration analyzed the results of studies on the advantages and disadvantages of antibiotics. They included a total of 21 studies involving nearly 8,000 pregnant women. They concluded that antibiotics can lower the risk of late-term miscarriages:

• 2% of women who didn't take antibiotics had a late-term miscarriage.
• 0.3% of women who took antibiotics had a late-term miscarriage.

Antibiotics had no influence on the risk of preterm birth or the risk of the woman’s waters breaking too soon (premature rupture of membranes). About 2% of the women stopped the treatment due to side effects. There is no evidence that the antibiotics have any long-term side effects or harm the child when used to treat bacterial vaginosis.

Most of the study participants had no symptoms. Their infection was detected during other routine pregnancy tests. If bacterial vaginosis starts causing symptoms during pregnancy, it is usually treated.