amenorrhea

Amenorrhea simply means the absence of menstrual periods. It is a symptom rather than a disease in itself — a signal that some part of the reproductive system or its hormonal control is not running as expected. Doctors split it into primary amenorrhea, where periods never begin by the expected age, and secondary amenorrhea, where previously regular periods stop for several months.

The single most common and important cause to consider first is pregnancy, which is entirely physiological. Beyond that, amenorrhea reflects a break somewhere along the hypothalamic-pituitary-gonadal axis or the outflow tract. The hypothalamus may suppress GnRH in response to severe stress, very low body weight, or intense exercise (functional hypothalamic amenorrhea); the pituitary may be at fault, as when a prolactin-secreting tumor shuts down gonadotropins; the ovaries may fail or be polycystic; or there may be a structural problem in the uterus or outflow tract.

Because the lining cannot shed without the right hormonal sequence, the loss of periods often points to either too little estrogen or an absence of ovulation and progesterone. A practical caveat: amenorrhea is not just an inconvenience — prolonged low-estrogen states, as in athletes or those with eating disorders, threaten bone health, so the underlying cause should be found and addressed rather than merely inducing bleeding.