Causes

The fungus candida albicans is responsible for most vaginal yeast infections.

Your vagina naturally contains a balanced mix of yeast, including candida, and bacteria. Certain bacteria (lactobacillus) act to prevent an overgrowth of yeast.

But that balance can be disrupted. An overgrowth of candida or penetration of the fungus into deeper vaginal cell layers causes the signs and symptoms of a yeast infection.

Overgrowth of yeast can result from:

• Antibiotic use, which causes an imbalance in natural vaginal flora
• Pregnancy
• Uncontrolled diabetes
• An impaired immune system
• Taking oral contraceptives or hormone therapy that increase estrogen levels

Candida albicans is the most common type of fungus to cause yeast infections. Yeast infections caused by other types of candida fungus can be more difficult to treat, and generally need more-aggressive therapies.