Amenorrhea means not having menstrual periods.
Amenorrhea is either primary or secondary.
Primary amenorrhea is not having menstrual periods by the age of 16. Secondary amenorrhea is the absence of three or more periods in a woman who has had regular menstrual periods. The pituitary gland and the hypothalamus, both located in the brain, must also be functioning properly. A problem with any of these parts of the body may keep you from having a period. The main cause of primary amenorrhea is late puberty.