Norethisterone contains a hormone which is similar to the hormone progestogen that is naturally produced by the body. It is used to treat a number of menstrual cycle conditions. Normally before a period is due there is a fall in the level of progestogen hormone in the body. When it falls below a certain level, the lining of the uterus is shed as menstrual period. By taking Norethisterone this is delayed until you stop taking the medication.
