Amenorrhea (ah-men-o-REE-ah) is the absence of menstrual periods. There are two types of amenorrhea, primary and secondary. With primary amenorrhea, menstruation has never occurred at all. In most cases, this is simply because of the late onset of puberty. If, however, the girl has not menstruated by the age 17, it is recommended she visit a physician for a gynecological examination.

Other causes of primary amenorrhea include anemia (uh-NEE-mee-uh), and disorders of the uterus, ovaries, or pituitary (pih-TOO-ih-tare-ee) gland. Sometimes there is false primary amenorrhea meaning the patient is menstruating, but the blood is prevented from reaching the outside because of a blockage.

Secondary amenorrhea refers to women who have missed three or more periods after their regular menstrual cycle has been established. The most common cause of secondary amenorrhea is pregnancy. However, menstrual patterns can also be altered by anemia, emotional stress, illness, certain medications, oral contraceptives, and excessive exercise. If you develop secondary amenorrhea and you are not pregnant, it is possible the timing of your menstrual cycle is off.