What is a luteinizing hormone (LH) levels test?This test measures the level of luteinizing hormone (LH) in your blood. LH is made by your pituitary gland, a small gland located underneath the brain. LH plays an important role in sexual development and functioning.In women, LH helps control the menstrual cycle. It also triggers the release of an egg from the ovary. This is known as ovulation. LH levels quickly rise just before ovulation.In men, LH causes the testicles to make testosterone, which is important for producing sperm. Normally, LH levels in men do not change very much.In children, LH levels are usually low in early childhood, and begin to rise a couple of years before the start of puberty. In girls, LH helps signal the ovaries to make estrogen. In boys, it helps signal the testes to make testosterone.Too much or too little LH can cause a variety of problems, including infertility (the inability to get pregnant), menstrual difficulties in women, low sex drive in men, and early or delayed puberty in children.Other names: lutropin, interstitial cell stimulating hormone
