Which treatments are effective for bacterial vaginosis?
Bacterial vaginosis can cause symptoms such as discharge with an unpleasant smell. The antibiotics clindamycin and metronidazole are both effective treatments for bacterial vaginosis. There has not yet been enough research on the possible benefits of lactic acid bacteria treatments.
Bacterial vaginosis is quite common and caused by changes in the vaginal flora that allow the rapid growth of specific types of bacteria (usually gardnerella).
The infection can cause a thin, grayish-white discharge with an unpleasant smell, but it often goes undetected. If it does produce symptoms, antibiotics can be used as an effective treatment, even during pregnancy. Treatment can help lower the slightly increased risk of miscarriage due to the infection, too.
How are antibiotics used?
Symptoms are usually treated with an antibiotic such as clindamycin or metronidazole – as a cream, vaginal suppositories or tablets, or oral tablets. Treatment can last one to seven days depending on the exact drug used, its form and the dose, and the severity of the symptoms. Your doctor can help you decide what type of treatment is most suitable for you.
If you've been prescribed antibiotics, it's important to be careful about using them correctly. That especially means using the medicine regularly and for as long as prescribed: Stopping early, for instance if the symptoms have already cleared up, contributes to the development of resistant strains of bacteria.
How effective are antibiotics?
Clindamycin and metronidazole are very effective against vaginosis symptoms. Studies on clindamycin cream treatments have shown the following:
- 50% of the study participants who didn't use clindamycin had no symptoms one to two weeks after placebo treatment.
- 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.
It's not uncommon for bacterial vaginosis to return after a few weeks. That happens quite often. About half of all women have symptoms again about one year after the first infection. If bacterial vaginal infections return more frequently, it may be a good idea to discuss options for preventive treatment with your doctor.
Studies have also looked into whether it's a good idea for your partner to also take antibiotics. But that didn't speed up the recovery time. It also hasn't been shown that treating your partner would prevent the infection from coming back.
What are the side effects?
Antibiotic treatment kills not only gardnerella bacteria, but also useful bacteria in the vaginal flora that work to keep other germs in check. This means that antibiotic treatment can sometimes end up causing a vaginal yeast infection (candida fungus). This happens to about 10% of women who use clindamycin or metronidazole. Itching and a thick, white discharge are typical signs of a yeast infection, and it can also be treated with medication.
Other side effects may also occur. Metronidazole tablets leave behind a metallic taste in about 10% of women. Less commonly, they cause nausea and vomiting. Clindamycin is very well tolerated when used as a cream, and aside from yeast infections it has no other known side effects.
Could lactic acid bacteria help?
Lactic acid bacteria are believed to help restore healthy vaginal flora and suppress harmful bacteria, but treatments that use lactic acid bacteria are not as well tested as antibiotics. There are hardly any studies testing them on their own – they are usually used in combination with antibiotics. But no evidence has been found that vaginosis clears up any better with this combination. Little is known about possible side effects.
Can vaginosis be treated during pregnancy?
Bacterial vaginosis that develops during pregnancy can slightly increase the risk of premature birth. The risk of a late-term miscarriage or stillbirth (between the thirteenth and twenty-fourth week of pregnancy) is also higher. In miscarriage or stillbirth, the child dies while still in the mother’s body.
The advantages and disadvantages of antibiotic treatment were analyzed in a Cochrane Collaboration systematic review. Researchers analyzed 21 studies involving nearly 8,000 pregnant women. The results show 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 premature births or on stopping a woman’s water from breaking sooner. About 2% of the women stopped treatment due to side effects. There is no evidence that antibiotics used to treat bacterial vaginosis have any long-term side effects or are harmful for the child.
Most study participants experienced no symptoms and their infection was detected during other routine pregnancy tests. If bacterial vaginosis starts causing symptoms during pregnancy, it is usually treated anyway.
Amaya-Guio J, Viveros-Carreno DA, Sierra-Barrios EM, Martinez-Velasquez MY, Grillo-Ardila CF. Antibiotic treatment for the sexual partners of women with bacterial vaginosis. Cochrane Database Syst Rev 2016; (10): CD011701.
Brocklehurst P, Gordon A, Heatley E, Milan SJ. Antibiotics for treating bacterial vaginosis in pregnancy. Cochrane Database Syst Rev 2013; (1): CD000262.
Huang H, Song L, Zhao W. Effects of probiotics for the treatment of bacterial vaginosis in adult women: a meta-analysis of randomized clinical trials. Arch Gynecol Obstet 2014; 289(6): 1225-1234.
Oduyebo OO, Anorlu RI, Ogunsola FT. The effects of antimicrobial therapy on bacterial vaginosis in non-pregnant women. Cochrane Database Syst Rev 2009; (3): CD006055.
Tan H, Fu Y, Yang C, Ma J. Effects of metronidazole combined probiotics over metronidazole alone for the treatment of bacterial vaginosis: a meta-analysis of randomized clinical trials. Arch Gynecol Obstet 2017; 295(6): 1331-1339.
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