A vaginal yeast infection is usually caused by a fungus called Candida albicans which is normally found in small amounts in the vagina.

It's estimated that three out of four women will have a yeast infection in their lifetime. Factors that contribute to vaginal yeast infection include pregnancy, diabetes, and the use oral contraceptives, steroids, and antibiotics. Yeast infection is also more common after menopause due to declining estrogen levels, which thin the vaginal walls.