* Eating disorders, such as
anorexia or bulimia. For more information, see the topic
Anorexia Nervosa or Bulimia
Nervosa.
* Increased exercise. Missed periods are common in endurance athletes.
* Emotional stress.
* Illness.
* Travel.
* Medicines such as hormonal birth control methods, which may cause lighter, less frequent, more frequent, or skipped periods or no periods at all.
* Hormone problems.