A normal vagina contains many types of microorganisms -- bacteria and yeast -- known as the vaginal microbiome. Anything that disturbs this microbiome may increase the risk for infection by disease-causing microorganisms. Probiotics are live microorganisms that may provide a health benefit. Probiotics are sometimes used to prevent or treat vaginal infections. They can be taken by mouth or as suppositories inserted directly into the vagina. Scientific research published to date is conflicting regarding whether or not probiotics improve vaginal heath.
The most important organisms in the vaginal microbiome are Lactobacillus bacteria species. Lactobacilli act as a barrier to infection by preventing disease-causing organisms from attaching to the vagina surface and by producing chemicals such as lactic acid that inactivate or kill other organisms. The organisms of the vaginal microbiome change over time. The drop in estrogen levels that occurs after menopause leads to decreased amounts of Lactobacillus, increasing the risk of vagina or urinary system infections.
Bacterial vaginosis, or BV, is a condition resulting from the overgrowth of one of several types of bacteria normally present in the vagina, upsetting the natural balance of vaginal bacteria. BV may cause vaginal discharge, odor or irritation. It may also increase the likelihood of complications if a woman is pregnant. According to a review article published in the March 2014 issue of “Archives of Gynecology and Obstetrics,” low levels of vaginal Lactobacillus are associated with the development of BV. BV is the most common gynecologic condition for which probiotic therapy has been studied. Although some studies have found that probiotic therapy reduces BV, others studies have not found it to be effective, according to the authors of the same “Archives of Gynecology and Obstetrics” review article.
Vaginal Yeast Infection
Vaginal yeast infection is one of the most common gynecologic conditions for which women seek treatment. Often women try to diagnose themselves and many over-the-counter medications to treat yeast infections are available. But these medications are not always effective. Probiotics may lower the risk of vaginal yeast infection by preventing the yeast from attaching to the vaginal wall. However, very few good quality studies have been conducted to determine whether they are effective. In a June 2009 review article published in “Journal of Chemotherapy,” the authors found only 2 previously published good studies that had evaluated this -- only 1 of these reported that probiotics helped prevent vaginal infections.
Urinary Tract Infection
Urinary tract infections, or UTI, occur when bacteria normally living in the vagina and intestinal tract ascend into the bladder. Many women, especially after menopause, experience repeated episodes of UTI, even after treatment with antibiotics. It is currently unclear whether probiotics are helpful in preventing recurrent UTI. A review article published in the November 2008 issue of “Clinical Therapeutics” noted that probiotics administered as vaginal suppositories prevented UTI in only 1 of the 3 previously published good quality studies that evaluated their effectiveness.
Considerations With Probiotic Therapy
Results from studies of probiotics for vaginal health may be difficult to interpret. Different strains -- subtypes -- of the same probiotic species can differ in their properties, so results from one study may not apply to other strains. Additionally, both the first and second words of the bacteria name are important. For instance, the benefits of eating yogurt, which contains mostly Lactobacillus acidophilus, may differ from the benefits of a capsule containing Lactobacillus crispatus or Lactobacillus jensenii. In some women, probiotics can cause side effects, such as mild gas or bloating. Furthermore, antibiotics may interfere with the effects of probiotic therapy. Additional research is clearly needed to determine whether probiotics are truly effective in improving vaginal health and if so, which are best.
- Clinical Infection Diseases: Probiotics: Definition, Sources, Selection, and Uses.
- Translational Research: Understanding Vaginal Microbiome Complexity From an Ecological Perspective.
- Archives of Obstetrics and Gynecology: The Role of Lactobacilli and Probiotics in Maintaining Vaginal Health.
- American Journal of Clinical Nutrition: Probiotic Agents to Protect the Urogenital Tract Against Infection.
- International Journal of Antimicrobial Agents: A Pilot Study Evaluating the Safety and Effectiveness of Lactobacillus Vaginal Suppositories in Patients With Recurrent Urinary Tract Infection.
- JAMA: Probiotics Revisited
- Clinical Therapeutics: Use of Lactobacillus Probiotics for Bacterial Genitourinary Infections in Women: A Review