What is amenorrhea?

Amenorrhea is the medical term for the absence of menstrual periods, either on a permanent or temporary basis. Amenorrhea can be classified as primary or secondary. In primary amenorrhea, menstrual periods have never begun (by age 16), whereas secondary amenorrhea is defined as the absence of menstrual periods for three consecutive cycles or a time period of more than six months in a woman who was previously menstruating.

The menstrual cycle can be influenced by many internal factors such as transient changes in hormonal levels, stress, and illness, as well as external or environmental factors. Missing one menstrual period is rarely a sign of a serious problem or an underlying medical condition, but amenorrhea of longer duration may signal the presence of a disease or chronic condition.