The human menstrual cycle, something that most of us take for granted, is actually orchestrated by a complex interaction between the brain, the ovaries, and the uterus. The Conductor of this orchestra resides in a very small area of the brain called the hypothalamus.
When the cyclic arrival of the menses is halted, otherwise known as amenorrhea, the culprit can be the brain, the ovaries, the uterus or it may be due to medication side effects or other hormonal abnormalities. As a detective, the task for the reproductive endocrinologist is to discover the cause of the disruption and try to treat or compensate for it. After a thorough investigation, if no abnormalities are found in the ovaries, the uterus or other hormone systems, then the source is presumed to be in the hypothalamic region of the brain.
Hypothalamic amenorrhea is essentially the result of a built-in mechanism in the human species for self-preservation and survival. Reproduction is most optimal in a safe environment with adequate nutrition and in the absence of threats from predators. In the hunting and gathering days of the human race, when food was not consistently available and therefore timing was not optimal for pregnancies, the hypothalamus would decrease its stimulation of the ovaries with the intent of temporarily ceasing ovulation until food sources becomes more abundant. When humans were out in the plains constantly being hunted and chased by predators, the hypothalamus would sense the psychological and physical stress as inappropriate timing for reproduction, and again it would respond by decreasing its stimulation of the ovaries, sending ovulation into a hiatus until the environment is safer.
Under modern living conditions, the majority of the people are no longer facing scarcities in food supply or being chased by tigers and lions; however, the hypothalamus has not evolved with our environment and still maintains its primitive survival instincts. Self-imposed dietary restrictions and/or weight loss and having extremely low body fat content, albeit intentional, can be misinterpreted by the hypothalamus as not having adequate food supply. Intense exercises may be misconstrued as being chased by predators. Psychogenic stress imposed by our environment or internally by personalities that strive for perfection can also elicit constant stress response that is essentially equivalent to that of trying to escape from life-threatening situations. The hypothalamus does not discriminate the source of stress and reacts in its innate fashion to stop ovulation under these circumstances which results in hypothalamic amenorrhea.
The initial approach to treating hypothalamic amenorrhea is to try to eliminate or at least reduce some of the misinterpreted signals by the brain. Weight gain, increasing caloric intake, increasing body fat mass, decreasing exercise intensity and frequency may be helpful if the source of the hypothalamic amenorrhea is due to energy deficiency. Cognitive therapy may be helpful for patients who chronically experience self-imposed or environmentally induced stress. In circumstances where these measures are unable to allow the hypothalamus to recover its function, medications to directly stimulate the ovaries may be used to temporarily resume ovulation for fertility purposes. For women with hypothalamic amenorrhea who are not trying to conceive, it is still a good idea to consult a reproductive endocrinologist to discuss the longer term health risks such as osteoporosis. With appropriate treatment, the negative impact of hypothalamic amenorrhea can be minimized.