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.
Review Date 4/19/2022
Updated by: John D. Jacobson, MD, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.