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Are you trying to get pregnant and wondering if ovulation tests can help you along your journey?
Many women swear by ovulation tests for getting pregnant.
But it may surprise you to know that these may not work for everyone.
Let’s take a look at what factors affect the accuracy of ovulation tests. Plus, a few troubleshooting tips.
First, let’s review the basics of ovulation test kits.
What are ovulation tests/ ovulation predictor kits (OPKs)?
An ovulation test or ovulation predictor kit (OPK) is an at-home test that can help you detect when you ovulate. It does this by measuring the amount of luteinizing hormone (LH) in your urine.
Let’s have a quick biology lesson to better understand how ovulation tests work:
- When you’re close to ovulation, a gland in your brain called the pituitary gland releases luteinizing hormone (LH).
- LH levels rise at a rapid rate around 24-36 hours before ovulation; this is called the “LH surge”.
- This LH surge triggers ovulation and signals your ovary to release a mature egg.
- The mature egg is then swept into your fallopian tube. It can be here fertilized for up to 24 hours.
- Meanwhile, the empty follicle forms a structure called the corpus luteum which secretes progesterone.
- If fertilization occurs, then the embryo travels to your uterus for implantation. When an embryo implants, your progesterone levels rise further. This helps maintain the health of the pregnancy.
- If fertilization does not occur, then your progesterone levels drop. This causes your uterine lining to slough off and your period to begin.
Ovulation tests help you figure out when your fertility is the highest by detecting your LH surge. You have the highest chance of getting pregnant during your fertile window which spans around 6 days. This includes 4 days before, the day of, and the day after ovulation. Additionally, some OPKs also detect estrogen to give you a more accurate picture of your fertile window.
Even though the egg only sticks around for about 24 hours after release, sperm can hang out in your reproductive tract for up to 5 days. It is beneficial for sperm to already be present around the time of ovulation, so this is why it is recommended to have sexual intercourse every day or every other day during your fertile window.
This gives you the highest chance of getting pregnant.
Now that we understand how OPKs can be useful, let’s look at how accurate they are.
How accurate are ovulation tests?
Ovulation tests are accurate 9 out of 10 times if you meet the following criteria:
- You have regular cycles.
- You use the OPK correctly.
- Your LH levels fall in the average threshold range.
However, you may not meet this criteria. Inaccurate results could result because of the following:
- You may be one of 69% of women who report their cycle varies by up to 6 days. While it’s normal to have variations, they need to be accounted for while taking a test.
- OPKs need to be checked for expiry. You can do this by inserting the strip into your first-morning urine for the instructed amount of time.
- The threshold range for ovulation tests varies, typically around 20-40 mIU/mL. Your LH levels may be lower or higher than the threshold. LH levels vary considerably, they may be as low as 12.2 mIU/mL in some women or as high as 118.0 mIU/mL in others, and both these values can result in ovulation!
Can I use ovulation tests if I have irregular cycles?
You can use ovulation tests if you have irregular cycles, but you will have to do a bit of math to determine when to start testing.
Take your shortest cycle from the past 6 months and subtract 12-14 days to get an idea of when you had approximately ovulated. Begin testing 4 days before this for all your cycles, regardless of length. For example, if your shortest cycle was 25 days, then you would start testing for ovulation around days 7-9 for all your cycles.
Remember, with irregular cycles, it’s always better to test for more days so that you don’t miss your fertile window.
Can ovulation tests be wrong?
Yes, they can be wrong. Let’s look at some of the pesky factors that can throw your ovulation tests off track, causing you to receive a false positive or a false negative test.
False positives
- Cross-reactivity
Hormones such as FSH, TSH, LH, and hCG have a similar molecular structure. The picture below illustrates this.
Each hormone is made of alpha and beta subunits. The alpha subunit is the same in all four hormones. The beta subunit is what gives each hormone its unique characteristics.
Most ovulation predictor kits only test alpha LH. Since the tests do not test for beta LH, there is a risk for cross-reactivity with hormones such as FSH, TSH, and hCG which gives a false positive.
- Luteinized unruptured follicle (LUF) syndrome
In luteinized unruptured follicle syndrome, your LH levels rise but the follicle does not rupture. This means no egg is released.
OPKs will show you’ve ovulated since LH has risen. But it is a false positive since no egg was actually released. It is said to affect about 10% of the menstrual cycles of normal fertile women.
- PCOS
PCOS causes hormonal imbalances that affect ovulation. PCOS may cause high levels of luteinizing hormone throughout your cycle. You may also experience multiple LH peaks and multiple positive ovulation tests. However, you do not ovulate after each peak.
Read More: Using Ovulation Tests with PCOS: Can You Trust the Accuracy?
- Pregnancy
The pregnancy hormone, hCG, is secreted by the placenta during pregnancy. It rises during pregnancy and remains at about 30,000 IU/mL throughout pregnancy. After birth, hCG levels rapidly decline but may remain in the body for up to 6 weeks.
Ovulation tests may mistake hCG for luteinizing hormone due to their similar molecular structure. This is why if you are pregnant or have recently become pregnant you could receive a false positive.
- Medications
Certain medications, including fertility medications, may affect the accuracy of ovulation kits. Here are a few medications that can result in a false positive test:
- Menotropins
- Injections containing hCG
- Clomiphene citrate
- Danazol
Read More: False Positive on an Ovulation Test: 6 Reasons They Happen
False negatives
There are a couple of reasons you may experience a false negative.
- Your LH levels do not meet the threshold of the ovulation test. (Reminder, OPKs are based on a narrow range of around 20-40 mIU/mL.)
- You are missing your LH surge. This could be caused by testing on the wrong days or at the wrong time
How to improve the accuracy of ovulation tests?
Here are a few tips for improving the accuracy of ovulation tests:
- If you have a rapid LH surge, you may miss it if you only test once a day. So you can test twice a day.
- Make sure your ovulation strip is not faulty or expired.
- Test at the same time every day.
- Decrease your fluid intake a few hours before testing to avoid dilution.
- Keep testing until you receive a positive result. Don’t get discouraged and give up if you don’t ovulate smack dab in the middle of your cycle.
- Test your PdG levels as well to confirm if ovulation actually happened or not.
What are the other methods for detecting ovulation?
Let’s look at the other methods for detecting ovulation and their accuracy.
- Cervical mucus
You can see your cervical mucus change throughout your menstrual cycle. It can help you determine when you are close to ovulation. During your fertile window, your cervical mucus resembles raw egg whites; it is clear and stretchy.
Know More: Cervical mucus 101: What can your cervical mucus tell you about your body?
- Basal Body Temperature (BBT)
Thanks to progesterone, your basal body temperature rises by 0.5-1 degree Fahrenheit after ovulation. Your BBT will then stay elevated until right before your next period.
Once you notice the increase in temperature, you can assume you have ovulated.
At least that is what we used to believe. The current literature does not recommend using BBT if you are trying to get pregnant. BBT is one of the most unreliable forms of detecting ovulation. Many factors affect BBT such as exercise, stress, and fever.
- Follicular scan
A follicular scan is a series of ultrasound vaginal scans that can show exactly when ovulation occurs. This is a reliable test but it is expensive and cannot be done in the comfort of your home.
Know More: A Closer Look At Follicular Scanning For Ovulation Tracking: Is It Worth All The Inconvenience?
- The Inito Fertility Monitor
The Inito Fertility Monitor is an easy-to-use comprehensive fertility monitor. It measures estrogen, FSH, LH, and PdG (urine metabolite of progesterone) with a single test strip to predict your fertile window and also confirm ovulation. Unlike OPKs, Inito does not rely on thresholds and you receive real numerical values of your hormones.
How do these methods compare to ovulation tests?
Take a look at this data:
Key Takeaways
- Ovulation predictor kits measure luteinizing hormone in your urine to predict ovulation so you can time intercourse for the highest chance of getting pregnant. Some OPKs also measure estrogen.
- Ovulation tests are accurate 9 out of 10 times if you have a regular cycle, you’re using the test correctly, and your LH levels fall within threshold values.
- Underlying conditions or medications can alter the accuracy of ovulation kits.
- You can increase the accuracy of OPKs by following the manufacturer’s instructions, testing at the same time each day, continuing to test until you receive a positive result, and using an additional method of tracking your ovulation such as BBT or the cervical mucus method.
- There is a learning curve with ovulation tests. Be patient and don’t give up. You got this!
Frequently asked questions
What are the odds of getting pregnant on an ovulation test?
Your chances of becoming pregnant depend on many factors. But ovulation tests may improve your chances! Studies show twice as many women get pregnant using ovulation tests as compared to women who don’t use ovulation tests.
Is it possible to get a positive ovulation test result but not actually ovulate?
Yes, it’s possible! In some instances, an underlying issue may be causing a false positive. For instance, PCOS can cause several LH spikes, but ovulation does not occur. Other causes can include pregnancy, menopause, and certain prescription medications. Using the Inito Fertility Monitor can help avoid this confusion. Inito measures your PdG (urine metabolite of progesterone) levels to confirm if you have actually ovulated.
Read More: False Positive on an Ovulation Test: 6 Reasons They Happen
What should I do if I’m not getting positive ovulation test results?
You might be missing your LH surge or your LH levels are lower than threshold values. Begin testing earlier in your cycle and test twice a day until you receive a positive result or start your next period. You may also try combining ovulation tests with other methods such as tracking BBT and cervical mucus. Contact your OB/GYN if you do not receive a positive test after a few months of testing.
Can I use ovulation tests if I have PCOS?
Hormonal imbalances in PCOS may provide misleading results with ovulation test kits. PCOS may cause you to have several LH peaks or high LH levels throughout your cycle which makes it difficult to track. Combining OPKs with other methods such as tracking BBT and cervical mucus may provide you with better results.
Read More: Using Ovulation Tests with PCOS: Can You Trust the Accuracy?
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