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FERTILITY EVALUATION

OVULATION PREDICTION

Urinary ovulation prediction kits are very useful and accurate.

How Urinary-Ovulation-Prediction Kits Work

Because LH is the hormone measured by the urinary-ovulation-prediction kits, these kits are more accurately described as urinary LH kits. The urinary-ovulation-prediction kits use chemicals to recognize the presence of LH in a small sample of urine. If the chemicals test positive for LH, you know that your LH rise is taking place and the egg will be released soon.

Exact prediction of ovulation is useful for timing intercourse and intrauterine insemination.  Commercially available “ovulation predictor kits” are generally quite accurate and easy to use.  They may be purchased over-the-counter at all drug stores.  We recommend “Clear Blue Easy Digital” as our patients have found this to be the most reliable and easiest to use.  These kits measure the hormone LH which is secreted in a large amount just prior to ovulation.  When the kit shows PEAK ovulation will occur within about 48 hours.  Insemination is timed on that basis.

Once you have started your testing, you should continue to do it daily—at about the same time every day. If you check your urine at about the same time every day, you should not miss the LH rise. 

It is important that you start testing your urine at least a few days before the expected day of the LH rise. Besides the fact that you should not start testing too late in the cycle and miss the LH rise, it will be beneficial to have a few days of negative test results so that you have something to compare with the positive one.  We recommend testing after you empty your bladder on awakening in the morning and then test your second urine specimen.  For patients who work nights and report difficulty detecting the urinary LH rise, we recommend doing urinary-ovulation-prediction kits every 12 hours. Since the LH release is related to sleep cycles, this will help reduce the chances of missing the rise in LH. 

The predictor kits are 90+ percent accurate.  The 10% inaccurate aspect is either a false positive-that is predicting ovulation when it is not forthcoming or a false negative-that is missing the LH hormone elevation.  We will help you with the timing and practicality of using these ovulation kits if we recommend them.

What If I Never Get a Positive Test?

There are a few possible reasons why you may not see a positive test result during a cycle:

  • The test was used too early or too late in the cycle. This is most commonly a problem for women with long menstrual cycles.
  • The kit was used incorrectly—user error. If you follow the instructions in the package insert of your kit this should not happen. The most common mistakes involve comparing the bands on the kit (if you are not using “Clear Blue Easy Digital”).  If you are unsure, repeat the test a few hours later.
  • The kit did not detect the LH surge that actually did occur—kit error. Most of the over-the-counter kits are very good, so this should only happen in aboutone out of ten kits used.
  • No LH surge occurred (you did not ovulate). You will probably not be able to distinguish this possibility initially from the others. However, most women who do not ovulate will not have their menstrual bleeding at the expected time. It is not uncommon for normal women to occasionally have a cycle without ovulating, which results in a delay in the onset of menstrual bleeding.