Fungi of the genus Candida normally live on the skin and inside the body (mouth, throat, gut, and vagina) without causing health problems. Research suggests about 20 percent of women have candida in the vagina that doesn’t cause infection. (1)
There are many species of candida, at least 15 of which are known to cause infections if they multiply out of control. (5)
In the United States, around 90 percent of vaginal yeast infections are caused by the species C. albicans. Most other cases are caused by C. glabrata. Less frequently, C. parapsilosis, C. tropicalis, and C. krusei cause vaginal yeast infections. (6,7)
Candida yeast cause an infection when something throws off the balance of microorganisms that live in and on your body, such as:
- Pregnancy
- Certain types of medication, including hormonal contraceptives (birth control pills, patches, or vaginal rings), antibiotics, and steroids
- Immune-suppressing diseases, including HIV
- Diabetes
- Obesity
- Stress and lack of sleep, which can weaken the immune system (2,3)
Additionally, certain lifestyle habits may also promote the growth of Candida, including:
- Being sexually active (vaginal yeast infections are not considered a sexually transmitted infection but they are more common in women who are sexually active)
- Eating a diet high in sugar (a yeast food source)
- Douching
- Other contraceptive use, including vaginal sponges, diaphragms, and intrauterine devices (IUDs)
- Maintaining poor vaginal hygiene
Wearing clothing that keeps the vaginal area warm and moist, such as synthetic underwear, pajama bottoms, and tight jeans or spandex (3,8,9)