Hello my friend Thanks for your question on HCM If you are not pregnant, other causes of missed or irregular periods include: 1.Excessive weight loss or gain. Although low body weight is a common cause of missed or irregular periods, obesity also can cause menstrual problems. 2. Eating disorders, such as anorexia or bulimia. For more information, see the topic Anorexia Nervosa or Bulimia Nervosa. 3.Increased exercise. Missed periods are common in endurance athletes. 4. Emotional stress. 5.Illness. 6.Travel. 7.Medicines such as birth control methods, which may cause lighter, less frequent, more frequent, or skipped periods or no periods at all. 8.Hormone problems. This may cause a change in the levels of the hormones that the body needs to support menstruation. You may need to do some tests: 1.Thyroid function test. Measuring the amount of thyroid-stimulating hormone (TSH) in your blood can determine if your thyroid is working properly. 2.Ovary function test. Measuring the amount of follicle-stimulating hormone (FSH) in your blood can determine if your ovaries are working properly. 3.Prolactin test. Low levels of the hormone prolactin may be a sign of a pituitary gland tumor. 4.Male hormone test. If you re experiencing increased facial hair and a lowered voice, your doctor may want to check the level of male hormones in your blood. 5.Ultrasound. This test uses sound waves to produce images of internal organs. You have to go to a specialist .But wile you can adjust lifestyle factors — such as too much exercise or too little food — can cause amenorrhea, so strive for balance in work, recreation and rest. Assess areas of stress and conflict in your life. If you can t decrease stress on your own, ask for help from family, friends or your doctor Hope this information is helpful Best regards