Polycystic ovarian syndrome, or PCOS, is a condition in which a woman’s levels of the sex hormones estrogen and progesterone are out of balance. This leads to the growth of ovarian cysts (benign masses on the ovaries). PCOS can cause problems with a women’s menstrual cycle, fertility, cardiac function, and appearance. Symptoms often begin soon after a woman first begins having periods. In some cases, PCOS develops later during the reproductive years, for instance, in response to substantial weight gain.To regulate your menstrual cycle, you may recommend combination birth control pills — pills that contain both estrogen and progestin. These birth control pills decrease androgen production and give your body a break from the effects of continuous estrogen, lowering your risk of endometrial cancer and correcting abnormal bleeding.