OPKs can be confusing…
but they don’t have to be!
OPKs measure the hormone called LH which is always present in our bodies. That means that you’ll always see a bit of a line regardless of when you test. But right before ovulation, your LH levels start to surge. It’s the final step needed for the egg to mature and be ready for ovulation! Your LH values can go from, for example, 2 to 20 (miU/ml) or from 7 to 100 (miU/ml), it differs from person to person. The exact numbers really don’t matter as much as the fact that all of a sudden, there’s a big increase in LH.
Some women don’t get an OPK that looks like the picture on the left, and that’s okay too. As long as the test line is as dark as the control line; consider yourself to be in your fertile window!
You can keep testing to see if your line gets darker, but don’t wait to have sex! For some, the surge takes a long time to go down and you may see your darkest OPK after ovulation. So if you wait, you’ve missed your fertile window as the egg isn’t viable for long after ovulation.
So what should you do when you get a positive OPK that looks like the image on the left OR right:
- Have sex that day, and the next two days. These are your most fertile days.
- Pay attention to your cervical mucus (CM). Do you notice any changes? Soon after you have ovulated, your CM changes from wet/sticky and stretchy, to dry or creamy. This means your fertile window is over.
- If you take your basal body temperature (BBT) you can expect a temperature rise after ovulation. Some may see an increase the day after ovulation, for others the rise happens over the course of a few days.