Please tell me how is a yeast infection caused?

Bacterial imbalance: Most yeast infections are caused by a fungus candia albicans which is normally present in small amount in vagina and is kept under control by haelthy bacteria called hemophulus, when that balance is compromised by antibiotics, hormone replacement, pregnancy, or there is immune problems due to diabetes or HIV than there is overgrowth of the fungus and that causes yeast or candia infection with discharg.