Pinpointing Ovulation – Do OPKs Work?

December 27, 2019 | Yesmom

Yes Mom

You are probably familiar with the basics of ovulation if you are trying to conceive. A mature egg is released once every month from one of the ovaries and is available to be fertilized. This is your peak fertility window and lasts for 12-24 hours making it the best and most convenient time to have sex when you’re trying for a baby. It occurs right in the middle of your cycle, but the cycle varies greatly for each woman and your ovulation is likely to vary from month to month. 

So if you are keen on conceiving, it’s imperative to know your fertility window for certain. This is where ovulation predictor kits come in. Since you are the most fertile during ovulation, these kits can help enhance your chances for success if you’re trying to get pregnant. But are they completely reliable? If you are a skeptic like all new mothers, here’s a handy guide for you.

How do they work?

It’s very simple- OPKs are nothing but at-home tests that you can use to determine when you’re ovulating. These kits will detect a surge in the production of the Luteinizing Hormone (LH). This occurs roughly 3 hours before ovulation and by timing intercourse shortly after LH surge you can increase the chances of bringing your egg and sperm together at that precise time when conception is most likely to occur. While the Luteinizing hormone is always present in your urine, it will increase during this time frame and trigger ovulation. 

To accurately detect a surge in LH, you may need to test for a few days. Most kits come with five to ten strips.

Are they accurate?

You should go for OPKs over any other methods of monitoring ovulation – they are more precise. If used correctly, the major brand OPKs are about 97% effective in detecting the LH surge that is largely used as a marker for ovulation. Now that is reassuring, isn’t it? However, it’s important to remember that OPKs determine whether your hormones are ready for ovulation, they will predict the ideal time to try to conceive but they won’t guarantee that conception will take place. Don’t worry, we will break it down for you.

The Cons

These kits measure the LH surge which in turn predicts ovulation but can’t confirm whether you have ovulated. Sometimes, following the surge, the egg may fail to emerge from its follicle- this condition is known as luteinized unruptured follicle syndrome or LUFS.

The mucus which you may experience as vaginal discharge, produced by the cervix in mid-cycle needs to have a certain consistency to be able to provide a fertile environment for the sperm to swim through. OPKs do not indicate whether this cervical mucus is conducive to fertilization. 

Also, OPKs tend to be more accurate for some women (whose cycles are regular and relatively predictable) than the rest. They won’t work if you have a condition like PCOS, have erratic period cycles, are over 40 years of age (women over 40 tend to have increased levels of LH at all times in their systems, rendering the tests invalid) or are taking certain medications. 

Often hormonal contraceptives may affect the results so it’s best to wait until your cycle stabilizes which will make it easier to monitor your ovulation. 

Are there any risks involved?

They are safe and effective if you want to find out when you’re ovulating and maximize your chances of conceiving. If used correctly, they are highly accurate so the real downside is that they are not completely foolproof. Sometimes they may indicate a false positive, you could end up testing too early or too late thereby missing your ovulation window altogether. They can also be a little expensive, although prices vary according to factors like the number of strips in the kit, the brand and whether the test has a digital reader. But if you are ready to conceive, we’d say don’t hesitate to buy an OPK. 

When should I pee on an OPK?

Unlike a pregnancy test, you need not take your ovulation test in the morning. However, you must test at approximately the same time each day and for most people, the most convenient time is late morning or early afternoon. It’s advisable to reduce your liquid intake for a couple of hours before testing because consuming excessive liquids may dilute the H in your urine.

Before selecting a brand, make sure you read the reviews and see which one makes sense for you. In a perfect world, Ovulation predictor kits would detect ovulation infallibly and you having sex while you’re ovulating will lead to pregnancy. Well, this is a perfect world and with these simple tests, you can now trust your fertility to this method. Sometimes you may not ovulate during a cycle and sometimes you may even miss your surge. So it’s advisable to combine OPKs with other methods and symptoms like cervical mucus, basal body temperature, the state of your cervix. OPKs are great but they are just one of many indicators. If your OPK does tell you that you experienced your LH surge, it’s time to get busy!

[1]Deborah Gaines. Ovulation Test Pros and Cons: Understanding OPKs. Available from: 

[2]Rachel Gurevich. Using Ovulation Test Strips to Detect Your Most Fertile Time. 2019, July. Available from: 

[3]Anon. Why you must pee on a stick. 2016, December. Available from: 

[4] Direito, Ana, et al. “Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women.” Fertility and sterility 99.1 (2013): 279-285. 

[5]Strauss, Jerome F., and Robert L. Barbieri. “Yen & Jaffe’s reproductive endocrinology: physiology, pathophysiology, and clinical management”. 8th Edition. Elsevier Health Sciences, 2018.