The hypothalamus and pituitary gland are the main centers controlling the hormones GnRH, FSH and LH, which in turn affect the ovary in order to begin and maintain a woman’s cycle. If one or more of these hormones is not being produced adequately then ovulation disorders are unavoidable, leading to infertility
The main causes of hypogonadotropic-hypogonadism are:
- Kallman Syndrome: A rare condition which causes the lack of GnRH production, leading to anovulation. It is genetically transmited.
- Severe weight loss (Anorexia nervosa): This is a psychosomatic disorder that is often found in teenagers and more commonly in girls rather than boys. It results in large weight loss and this can disturb the production of GnRH leading to amenorrhea.
- Obesity: Obesity is associated with low SHBG levels, high oestrogen and androgen levels which disturb the function of FSH and LH leading to hypogonadism.
- Intense physical exercise: Women who exercise excessively have a higher chance of anovulation due to lower levels of FSH and LH and higher levels of prolactin. A study found that two thirds of female runners have small ovulation phases in their cycles or complete anovulation.
In most cases when normal body weight has returned, fertility is restored without further treatment needed. Therefore it is important for women with high or low body weight to follow a correct diet before commencing treatment.
- Hypothalamus injury: The hypothalamus can be damaged by some tumors, tuberculosis, head injuries, radio-treatment etc. This causes disturbances to the production of GnRH, which leads to infertility.
Sheehan Syndrome: A rare condition which is characterized by a partial or total pituitary necrosis caused by bleeding and clotting of blood vessels. It can occur during labor and can be diagnosed by a difficulty to produce milk, hypotension and amenorrhea.
