Vaginal thrush is a vaginal infection caused by a fungus or yeast.
Yeast can also grow in the blood and cause a very serious infection.
Yeast germs grow in the vagina without causing infection. A yeast infection occurs when the yeast overgrows, causing symptoms. This often happens when the normal health of the vagina is disrupted. Almost all women get vaginal yeast infections from time to time. For example, taking antibiotics for a bacterial infection often will lead to an overgrowth of yeast in the vagina.