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.
If you are a woman that has not gone through menopause, your doctor may want to schedule your test at a specific time during your menstrual cycle.