One of the things about trying to conceive is that there are a number of different ways you can detect your fertility. Ultimately, all of these techniques, from cervical mucus charting to tracking your Basal Body Temperature, are designed to help you know when exactly it is that you ovulate. One way to help detect whether you’re ovulating is to watch for the LH Surge.

To detect an LH surge, you can use an Ovulation Predictor Kit, known as an OPK. The kit looks for that increase in Luteinizing Hormone that takes place just before you ovulate. That surge usually takes place about a day before ovulation, though for some women it can occur as many as three days before ovulation.

Now, the problem comes when you can’t detect your LH surge. In some cases, it means that you’re not ovulating. In other cases, however, it means that your LH surge may be mild enough that the OPK can’t detect it.

One of the most common reasons women fail to detect an LH surge is because they aren’t using the OPK at the right time. It’s hard to know when to test, for example, if you tend to have an irregular cycle. The instructions in the OPK are designed for a woman with a 28-day cycle, in many cases.

There is also the possibility that the OPK or the individual test strip that you used was defective. This is a relatively rare occurrence, however. You might not have used the strip correctly, either. But these are errors that are few and far between.

The most likely scenario if you’re not detecting an LH surge is that you’re not ovulating, and that it may be time to try some more intense fertility treatments, or even talk to your doctor.