Definition: Amenorrhea is the absence of menstruation. There are two types of amenorrhea: primary and secondary.
Primary amenorrhea refers to young women who have yet to experience the onset of menstruation by the age of 16. Secondary refers to the absence of menstruation in women who have previously menstruated.
Secondary amenorrhea can be a symptom of some types of cancer, as in pituitary tumors, and a side effect of cancer treatment. Chemotherapy induced amenorrhea is the result of the toxicity of some chemotherapy drugs. Women who undergo pelvic radiation therapy may also be at risk of amenorrhea.
Other conditions known to cause amenorrhea include polycystic ovarian syndrome, hyperthyroidism, pregnancy and lactation. Low body weight and excessive amounts of exercise are also linked to amenorrhea.
