amenorrhea

Amenorrhea or amenorrhoea is the absence of a menstrual period in a female organism which has reached reproductive age. Physiological states of amenorrhea are most commonly seen during pregnancy and lactation (breastfeeding). In humans, it is where a woman or girl who has reached reproductive age and who is not on birth control does not menstruate.

Amenorrhea is a symptom with many potential causes. Primary amenorrhea is defined as an absence of secondary sexual characteristics by age 13 with no menarche or normal secondary sexual characteristics but no menarche by 15 years of age. It may be caused by developmental problems, such as the congenital absence of the uterus, failure of the ovary to receive or maintain egg cells, or delay in pubertal development. Secondary amenorrhea, ceasing of menstrual cycles after menarche, is defined as the absence of menses for three months in a woman with previously normal menstruation, or six months for women with a history of oligomenorrhea. It is often caused by hormonal disturbances from the hypothalamus and the pituitary gland, premature menopause, intrauterine scar formation, or eating disorders.