Luteinizing hormone (LH) is a hormone that prompts ovulation, the release of an egg cell from the ovary, in women and the production of the hormone testosterone in men. Abnormally low luteinizing hormone levels in women can lead to irregular or completely absent ovulation and menstrual periods and ovarian cysts. Men with low LH levels may not produce enough testosterone, which may cause male lactation, decrease in sperm production and loss of sex drive. Infertility is a possible result of low LH levels in both sexes.
Approximately halfway through the menstrual cycle, an LH surge triggers ovulation. In this process, an ovarian follicle containing a mature egg bursts, releasing the egg. The remains of the follicle, now known as the corpus luteum, release progesterone to thicken the lining of the uterus so that the fertilized egg may implant. Women with low luteinizing hormone levels may not ovulate at all, or only sporadically. Likewise, menstrual periods may be irregular or absent.
Female patients with low levels of luteinizing hormone but adequate follicle stimulating hormone (FSH) levels may develop ovarian cysts. FSH stimulates the ovarian follicles and egg cells to mature in preparation for ovulation. Without an LH surge to allow the release of the egg, the follicle may fill with fluid and become a follicular ovarian cyst. Patients with these cysts may not experience any symptoms and the cysts typically disappear in a few months. Other women may experience bleeding, swelling, or pain that increases during sexual intercourse.
The effects of low luteinizing hormone production in men are primarily related to the resulting low levels of testosterone. Men may begin to secrete fluid from their nipples, much as a lactating mother would. Inadequate amounts of testosterone may also cause a drop in sperm production and in the man's sex drive. The loss of sexual desire can be gradual and therefore may go unnoticed. Some men develop erectile dysfunction as well, which is a much more obvious symptom that may prompt the patient to seek medical care, during which testing can reveal the low LH levels.
Treatment of this condition varies according to the cause of the low luteinizing hormone production. Artificial hormones may be administered via pills taken orally or injections. Women who wish to conceive a child may be prescribed LH and FSH therapy together to mimic the natural hormone changes in the menstrual cycle. Prolactinoma, an anterior pituitary gland tumor, may also cause low LH production in either gender, and may be treated with medication, surgery or radiation therapy.