One of the questions I m asked most often is Why is my period late? . Although, pregnancy is the most common cause of absence of menstruation (amenorrhea), many times, the women will also assure me that they are definitely not pregnant. So, what else can cause an absence of menstruation? Are you experiencing an unusual amount of stress in your life? Emotional stress is another possible cause of absence of menstruation. Eliminating the stress usually will cause menstruation to resume. What kind of medications are you currently taking? Certain medications such as contraceptives (oral, implanted, and injected), oral corticosteriods, antidepressants, antipsychotics, thyroid, and some chemotherapy drugs may cause amenorrhea for some women. You could have a hormonal imbalance. Polycystic Ovarian Syndrome is a common form of hormonal imbalance which may cause amenorrhea, as well as other symptoms that can include the other extreme with excessive bleeding (menorrhagia. Do you eat a healthy, well-balanced diet? Women who are malnourished or extremely underweight often experience amenorrhea. This occurs often in women with eating disorders such as anorexia or bulimia. How much do you workout? Do you dance or engage in sports? Vigorous exercise or athletic training can cause amenorrhea. Have you had your thyroid checked? Millions of Americans suffer from undiagnosed thyroid disease -- another possibility that should be explored by your physician. Do you have a chronic illness? If you have a chronic illness, or have been sick for an extended period, your menstrual cycle may be temporarily delayed. Once your body is well your period will usually return. Although rare, a pituitary tumor (a usually benign tumor) can cause an overproduction of prolactin which can interfere with the regulation of your menstrual cycle. If you have missed 3 or more menstrual cycles, and you haven t already sought professional medical advice, it s time to seek medical care to determine the underlying cause. Only a qualified health care provider can determine the cause of amenorrhea. You should also be alert to other signs that signal a need for medical attention. These signs include: Headaches Hair loss Vision changes Breast secretions or milk production Your doctor has several choices for diagnosing the cause of amenorrhea. He can do a progestin challenge with 7 to 10 days of medication to see if it triggers bleeding. This will tell him if menstruation stopped because of a lack of estrogen. Thyroid disease and pituitary disorders can be determined by blood testing. Pituitary tumors can be detected with diagnostic imaging equipment.