Amenorrhea is the lack of menstrual flow and can be a normal occurrence or a sign of malfunction or disease. In primary amenorrhea, menstruation does not begin when expected (by the age of 16). Secondary amenorrhea occurs when the normal established menstrual cycle is shut down for 6 or more months due to a condition other than pregnancy, breastfeeding or menopause.
Update Date 6/16/2010
Updated by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine.