Determination of pituitary hormone levels in patients with amenorrhea

Pituitary hormone level measurement is a commonly used clinical test for the diagnosis of amenorrhea, especially in the absence of experimental equipment for hormone measurement, it is of great help in evaluating ovarian and endometrial function.

The determination of pituitary hormones is particularly important for diagnosing the cause of amenorrhea. Patients with amenorrhea and low estrogen should further measure the levels of blood follicle-stimulating hormone, luteinizing hormone and prolactin. If the follicle-stimulating hormone and luteinizing hormone are elevated, it indicates ovarian amenorrhea. If the follicle-stimulating hormone and luteinizing hormone are low, the cause may be in the pituitary or hypothalamus; follicle-stimulating hormone and luteinizing hormone are equivalent to normal follicular phase levels, and amenorrhea is caused by hypothalamic secretion dysfunction; if luteinizing hormone is elevated and follicle-stimulating hormone is relatively insufficient, the diagnosis of polycystic ovary syndrome should be considered; if prolactin is abnormally elevated, amenorrhea is caused by hyperprolactinemia, and the cause of hyperprolactinemia should be further examined, with special attention to the possibility of pituitary tumors.

When the levels of follicle-stimulating hormone and luteinizing hormone are both low, the pituitary stimulation test can further distinguish whether the lesion is in the pituitary or in the hypothalamus. The pituitary stimulation test is to dissolve 100μg of luteinizing hormone-releasing hormone in 5ml of normal saline and inject it intravenously within 30s. Blood is taken before injection and 15, 30, 60, and 120 minutes after injection to measure luteinizing hormone. If the luteinizing hormone value rises to more than 3 times before injection 30 to 60 minutes after injection, it indicates that the pituitary function is good and the response to the hypothalamic hormone luteinizing hormone-releasing hormone is normal. The cause of amenorrhea is in the hypothalamus or higher. If the luteinizing hormone does not increase or the increase is not obvious after injection, it indicates that the pituitary lacks response and the cause of amenorrhea may be in the pituitary.