Whether you're trying to conceive, prevent pregnancy, or understand your body better, OPKs (Ovulation Predictor Kits) can be pretty darn helpful. Ovulation predictor kits react to the luteinizing hormone that is present in urine, which is at its peak 12–36 hours before the egg is released (or ovulation). While they are not my favorite way of determining ovulation, they are fairly easy to use and have a high accuracy rating. That being said, OPKs come with a few perimeters and a bit of a learning curve.
Below are the basics, pros and cons, tips, brands, and the problems we run across the most in the clinic.
Which to Choose
I've found that patients new to tracking their cycle will choose fertility monitors, such as ClearBlue, to track ovulation. These are a bit more high tech because they involve plugging the tests into a small machine that signals low, medium, or high fertility because they track both luteinizing hormone and estrogen levels.
These are as basic as it comes, They have one line for negative and two lines for positive, because they only track the rise in luteinizing hormone. When used every day you can see the line get darker and darker until it peaks.
OPKs are designed to test your urine for luteinizing hormone, which peaks mid-day, so I usually recommend testing sometime between noon-5pm. Begin testing 4-5 days prior to when it's estimated you ovulate, and test every day until after you get a positive. Some tests also often recommend you stop testing once you get a peak, but some women get at least 2 or 3 days of luteinizing hormone peaking before ovulation actually occurs. You can't know which day was your peak day unless you see another negative test again.
5 Common Problems We See In The Clinic
1. OPKs do NOT confirm that ovulation has occurred
Although both urine and saliva kits test for increased hormone levels prior to ovulation, they do not confirm whether ovulation actually occurred. An LH surge can sometimes occur without the release of an egg. Likewise increased estrogen levels are not always followed by ovulation.
2. It is possible to miss the LH surge
Because the LH surge can be extremely brief, it can be easy to miss. For this reason, some women may need to test their urine twice a day. If you find that your OPK is never positive, you may just be missing the LH surge. However, it could also mean that you’re not ovulating.
3. You may experience a ‘False’ LH surge
It’s possible to have a ‘false’ LH surge before the ‘real’ one occurs. This can result in timing intercourse too early and missing your true fertile time. Women with PCOS (Polycystic Ovary Syndrome) can continually produce false LH surges.
4. Knowing when to test can be difficult (and can end up being expensive!)
If you have irregular cycles, it can be a challenge to know when to begin testing with an OPK. Because the day of ovulation can vary widely between cycles and a urine based kit typically contains a limited number of tests, one kit is sometimes not enough. This can soon become expensive
5. Ovulation predictor kits will NOT alert you to a fertility problem
An OPK can only identify when you might ovulate and will not provide other valuable information about your fertility. This is why we always recommend to collect at least 3 months worth of data before "trying" to conceive and use in tandem with another tracking method until you have a good grasp on your cycle.
If you suspect you're not ovulating, or if you're having a lot of trouble figuring out if you are, make sure to work with a healthcare provider to create a plan that makes sense for you. If you'd like to work together to regulate your cycle you can learn more about acupuncture, send me a message, or make an appointment.