Luteinizing hormone (LH) plays a major role in ovulation. The level of LH increases dramatically as ovulation approaches.
Ovulation detection kits test for the LH in your urine. The test is positive when LH levels are high enough to trigger ovulation.
Studies show that ovulation detection kits are reliable but cannot tell you the exact moment when you will ovulate. Although the price of these kits varies between $25 and $50, these kits can help you more accurately predict the day of ovulation. They are more likely to be used by women who desire pregnancy, but they also can be used to help avoid pregnancy.