If you are trying to become pregnant, your doctor might want you to get an LH test several times to pinpoint when your body releases an egg, which is called ovulation. The amount of LH in your blood surges with ovulation. The LH surge signals that ovulation is about to start. Ovulation is the medical term for an ovary releasing a mature egg. A gland in the brain, called the anterior pituitary gland, produces LH. Levels of LH are low for most of the monthly menstrual cycle. first morning urine is used with the test, the first day of the LH surge may not be detected.