Before we get started, this type of infection is common. It’s not something that should be whispered in shame or make you feel dirty. Now that that’s out of the way: yeast infections are caused by an overproduction or imbalance of the naturally-oIf you’ve never had a yeast infection before, you should consult your doctor to confirm the diagnosis. Many women who think they have a yeast infection may actually have bacterial vaginosis (BV). BV is a common infection caused by the overgrowth of natural bacteria that reside in the vagina and is often accompanied by itching, white-gray discharge and a strong, fishy odor. Once you’re sure of the symptoms, over-the-counter vaginal antifungals can cure most yeast infections.ccuring candida fungus in the vagina. This fungus overgrows in moist, warm places, which is why wearing breathable, cotton underwear and quickly changing out of sweaty gym clothes is important. Other causes of candida overgrowth include antibiotics and other medications, a diet high in refined sugars, and a weakened immune system.