LH (luteinizing hormone) is the hormone responsible for triggering ovulation. The “LH surge” occurs 12-36 hours before ovulation. By detecting the LH surge, intercourse or insemination can be optimally timed with release of the egg(s).

We recommend Clear Blue ovulation predictor kits (digital kits are easier to read).

Electronic monitors may be used if they give a +LH. You can purchase these at most pharmacies.


To assist you with appointment scheduling, we recommend that you do your LH test in early morning, preferably before 12 noon, on the days indicated by your care provider.

Your urine should be concentrated by limiting fluid intake 4 hours prior to testing. This technique will increase your ability to obtain a reliable test result. If you are unsure of the test results, there is a 1-800-number listed on the kit where you can call for advice on their test kits.