Luetinizing Hormone

LH blood test measures the amount of luteinizing hormone (LH). LH is a protein hormone released by the anterior pituitary gland, pea-sized gland at the base of your brain. The pituitary is the “master control gland” – it makes hormones that affect growth and the functions of other glands in the body.

Functions

• In women, an increase in LH levels at mid-cycle causes ovulation.
• In men, LH stimulates production of testosterone, male sex hormone.

When is the test ordered?

• LH is often used in conjunction with other tests in the workup of infertility in both men and women.
• LH levels are also useful in the investigation of menstrual irregularities and to aid in the diagnosis of diseases involving the ovaries or testes.
• In children, LH is used to diagnose delayed and precocious (early) puberty.

Normal Results

• Adult male: 7 to 24 international units per liter (IU/L)
• Adult female: 5 to 20 IU/L (levels peak around the middle of the menstrual cycle)

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Abnormal results

Greater-than-normal levels of LH may indicate:

• Anorchia—absence of testes. Babies suffering from this disorder will have normal male internal and external genitalia (penis and scrotum), but the testes will be absent. This is known as congenital anorchia, or the “vanishing testes syndrome.”
• Hypogonadism– In girls, hypogonadism during childhood will result in lack of menstruation and breast development and short height. If hypogonadism occurs after puberty, symptoms include loss of menstruation, low libido, hot flashes, and loss of body hair.
• Klinefelter syndrome—Men have XY chromosomes—the carriers of genetic information, whereas boys suffering from this syndrome have an extra X chromosome. Children (male) born to women who have pregnancies post 35 are more likely to suffer from this syndrome.
• Menopause– Menopause is the transition period in a woman’s life when her ovaries stop producing eggs, her body produces less estrogen and progesterone, and menstruation becomes less frequent, eventually stopping altogether.
• Ovarian failure– Ovarian hypofunction is reduced function of the ovaries
• Polycystic ovary disease– Polycystic ovary disease is a condition in which there are many small cysts in the ovaries, which can affect a woman’s ability to get pregnant.
• Precocious puberty– Precocious puberty is when the body changes that normally occur during puberty happen earlier than normal. Puberty is the time in which sexual and physical characteristics mature.
• Turner syndrome– Turner syndrome is a genetic condition in which a female does not have the usual pair of two X chromosomes.
  Lower-than-normal levels of LH may indicate hypopituitarism– a condition caused by low levels of pituitary hormones.

Related Posts

1. Luetinizing hormone
2. Follicle Stimulating Hormone
3. Testosterone Hormone
4. Progesterone Hormone
5. Making Sense of Hormonal Profiles