Women can miss their periods without being pregnant due to medical problems, extreme amounts of exercise, medications and breast-feeding, according to WebMD. Young women who have just started menstruating and older women in perimenopause or menopause often experience missed periods as a normal part of life.
WebMD explains that extreme weight loss or gain and anorexia nervosa are both causes of missed periods, as are various pelvic disorders and hormone imbalances. Taking birth-control medications can cause a woman to miss her period. Endurance athletes sometimes find that their bodies stop menstruating. Many women's periods do not start after pregnancy until the woman stops breast-feeding. In addition, some women stop menstruating due to emotional stress.