Ovulation Predictor Kits: Are They Worth It?

July 25, 2022

Ovulation Predictor Kits: Are They Worth It?

Each month, our bodies prepare themselves for the miracle of life. A mature egg releases from one of our ovaries and eagerly awaits to be fertilized by that one lucky sperm. This 12- to 24-hour period - often referred to as the "fertile window" - is when we are at our highest fertility potential. If you are trying to get pregnant, an Ovulation Predictor Kit can be a useful tool in helping you to find your "fertile window”, but like many tools out there, they have their pros and cons. So the question is, are they worth it? Here's a look at how they work, how to use them, and whether they're right for you.

How They Work

Ovulation Predictor Kits (or OPKs for short), work by examining the rise in Luteinizing Hormone (LH) that occurs up to 44 hours before ovulation. A rise in LH signals the ovary to release an egg, so when your levels reach a certain threshold, it's reasonable to predict that ovulation will happen within the next 12 to 36 hours. The LH surge peaks ten to twelve hours before ovulation, and more often than not, occurs in the evening or after midnight.

Standard OPK test strips usually have two lines: One is the control line, which tells you that the test kit is working. The second line is the test line. You can tell that your LH level rises when the test line is similar in colour to the control line or darker. If you’re trying to conceive, this is one of the easiest ways to determine the best time to have intercourse.

How To Use Them

The Ovulation Predictor Kits (OPKs) test your Luteinizing Hormone (LH) levels in your urine, so all you have to do is pee on a stick and wait a few minutes for the indication line to show.

Ovulation usually takes place roughly halfway through your menstrual cycle, so using an ovulation predictor test a few days before your midpoint is optimal. You may want to test for a few days in order to find a rise in LH. The majority of ovulation tests come with five to ten test strips. If you use an ovulation test strip with a digital reader, it can compare your current hormone levels to those you've had in the past. It might be even easier to spot when your LH is going up this way.

To obtain the most accurate reading, remember to:

  1. Test first thing in the morning. Most women have a surge in LH in the morning, So it's best to use the LH kits first thing in the morning, before you’ve had a lot to eat or drink, to ensure reliable results.
  2. Make sure your urine is concentrated enough. Avoid peeing for an hour or two before the test, and try not to drink large amounts of fluid.
  3. Follow the package directions carefully. The more closely you stick with the manufacturer’s instructions, the more likely it is you’ll get good results.

If your luteinizing hormone levels are rising, it's time for the fun part! Have sex as soon as possible. Ovulation can happen within 36 hours of a rise in luteinizing hormone levels, so you should try to also have sex for two to three days after that as well.

couple in bed


The major benefit of OPKs is that they are simple to use. All you really have to do is pee on a stick. If you are someone who has regular cycles and no fertility-affecting issues like PCOS or Unruptured Follicle Syndrome, OPKs can be a very useful tool. As many OPK manufacturers will tell you, OPKs can tell when ovulation occurs up to 97 percent of the time, making them an enticing choice for many women.


The biggest disadvantage of OPKs is that they are not always accurate. For example, some women in their 40s have increased levels of LH in their systems at all times, making the OPK test invalid. PCOS and luteinized unruptured follicle syndrome (LUF) are two examples of conditions that make it difficult to use OPKs. In PCOS, women may experience several LH bursts each month, but ovulation does not always occur with each surge. This means that test results might be unreliable. Because an LH spike happens at unusual times, a person will have to take a test multiple days per cycle in order to be effective. An egg is never released in LUF; instead, an LH surge occurs without any eggs being ejected. Taking certain medications, such as fertility drugs, and antibiotics can all make ovulation test strips inaccurate. 

The other major drawback of OPKs is their ongoing expense. Prices vary depending on factors such as brand, the number of strips in the kit, and whether or not the kit is digital (more on this below). A box of basic test strips will set you back between $15 and $25, depending on how many there are in the box. Ovulation test strips or ovulation predictor kits with a digital reader will cost between $30 and $50+, depending on your budget.

ovulation strips

Considerations When Choosing a Kit

There are several different types of ovulation tests available, some more sophisticated than others. One thing to be on the lookout for when purchasing an OPK is what and how many hormones it checks, as well as how frequently. Many ovulation tests, regardless of whether they're digital or not, solely focus on your Luteinizing Hormone (LH) and its surge. While this hormone is crucial for ovulation, there are other hormones that can indicate when ovulation will occur even if they aren't in a peak state. The hormone Follicle Stimulating Hormone (FSH) decreases a few days before ovulation, as an example. As a result, if you simply examine LH and rely only on OPKs that concentrate on the surge in this hormone, you might miss some days of your fertile window.

Another consideration is how easy and transparent you want to make it for yourself to read and save your test results. Some kits claim to be "digital," but the technology varies greatly. For example, colorimetric digitization technology OPKs read the lines of your hormone test strips thoroughly through the lens of your smartphone camera and display the interpreted result right away on your phone!

Of course, the more advanced the kit will be, the higher the cost as well. the cost of OPK’s used every month can really add up, so you need to make the choice that’s best for you.

Other Ovulation Kits

A less precise and rarely used approach is a saliva test, which measures estrogen levels in your saliva as ovulation nears by examining the saliva under a microscope. Nearing ovulation, a distinct ferning, crystal-like pattern appears in the saliva. When ovulating, a look at your saliva under the test's eyepiece will reveal a microscopic pattern that resembles the leaves of a fern plant or frost on a window pane. This approach may work for some people, but there's no guarantee. Not all women get a nice "fern," but this test is cheaper than the kits and can be reused with good for the wallet. Also keep in mind that eating, drinking, and brushing your teeth might affect the results.

There are also devices that detect the salts like chloride, sodium, and potassium in a woman's sweat, which will vary throughout her monthly cycle. Called the chloride ion surge, this shift happens even before the estrogen and the LH surge, so these tests give a woman a four-day warning of when she may be ovulating, versus the 12-to-24-hour notice that standard ovulation predictors provide. The saliva test and the chloride ion surge tests have not been extensively investigated, with usage being far lower than for standard ovulation predictors.

fertility awareness method

Other Alternatives

A popular alternative to ovulation tests is the Fertility Awareness Method - a natural method that relies on women being in tune with their bodies and tracking their fertility signs. This method tracks multiple signs of ovulation including:

  • A slight fall, then rise in basal body temperature
  • Clear, thin and slippery cervical mucus (similar to that of egg whites)
  • A soft and open cervix
  • A slight twinge of pain or mild cramps in your lower abdomen.
  • Increased sex drive
  • Some light spotting.
  • Swollen vulva or vagina
  • Changes in mood
  • Etc...

In future posts, we'll dive deep into the Fertility Awareness Method and how you can make it work for you – either alone, or with the support of a Fertility Support Practitioner.

Ovulation predictor kits (OPKs) are a great option for trying to conceive, but there are pros and cons to using them. Some women have success with OPKs, while others find them expensive and unreliable. If you are willing to spend some time getting to know your body, they can be unnecessary.

If using an Ovulation Predictor Kit is something you is right for you and your partner, make sure to do your research first and choose the kit that meets your needs and budget. Remember to use it properly to maximize their effectiveness. And most importantly, remember to have fun in the process!!! 

Happy couple with positive pregnancy test

Explore details of the Fertility Awareness Method and how it can help you conceive.


Ewa Reid is a Registered Holistic Nutritionist, certifying Fertility Support Practitioner, nutrition & fertility educator, wife, and mother. You can learn more about Ewa on our About page.

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