This medication is used to treat women with abnormal bleeding from the uterus. It is also used to treat women who have stopped having menstrual periods for several months (amenorrhea) but who are not pregnant or going through menopause. In addition this medication is used to treat a condition (endometriosis) in which tissue that normally lines the inside of the uterus is found outside the uterus in the abdomen/pelvic area causing painful/irregular periods. Norethindrone is a type of female hormone (progestin). It is like the hormone progesterone that your body makes naturally. This medication works by stopping the normal growth of the uterus lining during the menstrual cycle and signaling hormone changes in the uterus to restore normal menstrual periods.