Do Pregnancy Tests Expire?

Have you ever taken a pregnancy test and been uncertain about the results that you received? Perhaps you’re wondering whether you took the test correctly, or if your test is faulty or expired. Do pregnancy tests go out of date?

The simple answer to this last question is yes, pregnancy tests can and do have an expiry date, which you can usually find printed somewhere on the packaging, or on the test stick itself. Most tests will last between 1 and 3 years from the manufacturing date.

It is generally good practice to check the date before using a pregnancy test, particularly if you have kept it in your cupboard for some time, as using an expired test may give inaccurate results.

In this article, we’ll be diving into how pregnancy tests work, the importance of the pregnancy test expiry date and how it may affect your results, and how to best store and use your at-home test for the most accurate results. Let’s get started.

How Do Pregnancy Tests Work?

Firstly, to understand why the expiration date may affect test results, it can be helpful to gain some background knowledge on how pregnancy tests work.

All at-home pregnancy tests gather their data through detecting the human chorionic gonadotropin (hCG) hormone, a special hormone that is only produced during pregnancy – often nicknamed the ‘pregnancy hormone’ for this very reason.

These tests pick up hCG by testing your urine, and can detect even the faintest trace. However, an expired test may begin to lose the sensitivity required to pick up these readings accurately, which is why expiration dates are so important.

Having an understanding of your menstrual cycle is also helpful if you are hoping to get pregnant. If you are trying to conceive, you may consider trying to use hormone-tracking tools such as the Mira Hormone Monitor, Mira App and Wands, which have been designed to provide you with a clearer picture of ovulation. 

By knowing when you are due to ovulate, you can begin to predict when you are at your most fertile, and to time having unprotected sex with your partner accordingly.

Types of Pregnancy Tests

There are two main types of tests available which can confirm whether you are pregnant:

• Urine Tests: Can be taken and confirmed with your doctor, or at home, using store bought or practitioner provided tests. These home pregnancy tests (HPTs) often use test strips or digital screens to clearly display results.

• Blood Tests: Can only be carried out with your healthcare provider. Your test is then taken away and studied in a lab, and can offer you even more accurate results.

There are various factors that may affect the accuracy of your results, particularly with HPTs. Here are a few examples:

• Freshness of the test

• Urine concentration

• Testing time

Now, let's unpack what happens when a pregnancy test expires, and go through some useful tips and tricks that can help you test for the most accurate results.

What Happens When a Pregnancy Test Expires?

Chemical Breakdown

Pregnancy tests include special chemicals that allow them to detect the hCG hormone. A key reason why tests have an expiration date is because these reactive chemicals may begin to degrade over time, making them less sensitive to hCG and risking inaccurate readings when used.

Higher Chance of False Negatives

If your test detects even the faintest trace of hCG, you will receive a positive test result, meaning that you are pregnant. However, an expired test may not detect hCG properly, risking you receiving a negative result, despite actually being pregnant. This is called a false negative.

If you think you are pregnant but have received a negative result, try testing a second time (making sure to use an in-date test) to be sure of the results.

False Positives Are Rare

Similar to false negatives, sometimes an expired test may give you a false positive, meaning that the test is saying you are pregnant, when in reality you are not.

Although false positives are rare, and far less likely than false negatives, they are possible – particularly with expired tests, due to potential faulty strips or unwanted exposure to moisture. 

Put simply, pregnancy tests need to be within date, kept in the best possible condition, and used correctly to ensure scientific accuracy in their results.

How to Check If Your Pregnancy Test Is Expired

Where to Find the Expiration Date

If you are concerned that you may have used an expired pregnancy test, do not worry! If you’d like to check, the expiration date on pregnancy tests is usually easy to find – try looking on the box, wrapper, or even the test stick itself for a printed date.

If you can only see a manufacturing date and not an expiry date, remember that pregnancy tests usually expire after 1 to 3 years from manufacturing, so this can help you figure out how old your test is and whether it could be expired.

If you’re still unsure, try again a new in-date test, where you can be confident that it will give you the most accurate results.

Signs of a Faulty or Expired Test

Sometimes, pregnancy tests can show signs of being faulty or expired, which you can look out for to check whether your test is fit for use.

Here are some important signs to be aware of when checking:

• No control line appears after testing (indicating the test is defective)

• Incomplete or faint lines that don’t match expected results

• Results take too long to appear, or don’t appear at all

• Packaging is damaged from heat, moisture, or improper storage

If you spot any of the above signs when using your test, take a second test that shows no sign of being faulty or expired to confirm your results.

Can You Still Use an Expired Pregnancy Test?

You may still be wondering, “Do expired pregnancy tests work?” Perhaps an expired test is currently your only available option and you’re anxious to find out your results.

Technically, you can use a pregnancy test out of date, as there are no harmful side effects from using one, however the result may be unreliable, which is something to take into consideration.

As false negatives are much more likely when using an expired test, if you do receive a negative result, we suggest testing a second time with an in-date test after a few days to confirm the result. For further confirmation and even more accurate results, you may consider talking to your doctor about having a blood test to confirm pregnancy. 

While expired tests are not unsafe to use, and there are steps you can take to confirm the results, the general recommendation is not to use expired tests.

How to Store Pregnancy Tests for Maximum Accuracy

Best Storage Practices

It’s worth noting that sometimes improper storage can also affect the accuracy of an at-home pregnancy test, even if they have not yet passed their expiry date.

Storing your test correctly can help you avoid this and ensure maximum accuracy of results when testing. Most tests tend to include storage instructions written somewhere on the packaging, but generally, you should keep your pregnancy tests in a dry place at room temperature.

Avoid storing in extreme heat or cold environments, or humid spaces that may risk exposing the test to unwanted moisture. This means that bathrooms, often the most humid rooms in the home, are not recommended for storing your pregnancy tests.

It’s also good practice to not open your test until you’re about to use it, as unwanted exposure to air may also affect the accuracy of results when testing.

Common Mistakes That Can Ruin a Test

With the previous information in mind, there are some common mistakes people make when storing their tests that may risk ruining a pregnancy test.

While avoiding extreme heat or cold environments may seem straightforward, even forgetting your test and leaving it in your car, which may become very cold in winter or very hot under the summer sun, could damage the test.

Leaving a test in your fridge or freezer at home, or in direct sunlight, such as on your windowsill or in a particularly sunny spot in the home, is also not recommended. 

Many people store their tests in the bathroom for privacy or ease of use, as this is where they are most likely to use them. However, leaving your test in a humid room such as a bathroom can risk shortening the shelf life of your test and as a consequence, make it inaccurate.

Be sure to check if the test you’re about to use shows any signs of physical damage or being unsealed. Damage or premature exposure to air may affect the test’s ability to properly detect hCG and increase the chance of inaccurate results.

When to Take a Pregnancy Test for the Most Accurate Results

So, by now you should feel more confident in how to spot a faulty or expired test, and how to correctly store your test to preserve its accuracy. We’ll now discuss some useful tips on when to take your pregnancy test for the most accurate results.

Generally, it’s best to take your pregnancy test first thing in the morning, as morning urine is more likely to have the highest concentration of hCG, making it even easier for the test to detect.

We also suggest waiting at least one day after a missed period before taking a pregnancy test for maximum accuracy, as this will allow enough time for your body to begin hCG production if you have conceived.

If after testing you are still unsure, are worried that you’ve used a damaged or expired test, or simply wish to double check, try testing 48 hours later for further confirmation on your results.

For even more accurate early detection, track your basal body temperature (BBT) with the Mira Basal Body Thermometer and monitor your hormone levels with the Mira Hormone Monitor. Together, these tools help you evaluate your unique hormonal patterns throughout the menstrual cycle and determine the best time to test for pregnancy.

Disclaimer: The Mira Hormone Monitor and Wands are not intended for use in the detection or monitoring of pregnancy.

Final Thoughts

To wrap up this article, let’s go over the basics one last time. 

Can pregnancy tests go bad? Ultimately, pregnancy tests do expire, and using a test that has passed its expiry date may lead to inaccurate results. Before use, make sure to store your tests properly and always check the pregnancy test expiration date, which you can usually find on the packaging, or on the test stick itself.

If you are at all in doubt or concerned about your test and the results you have received, take a fresh test or visit your doctor for further confirmation.

We hope you have found this article useful. Be sure to check out our blog for in depth conversations on other common pregnancy, fertility, and reproductive health concerns and questions.

Frequently Asked Questions

Can a positive result be missed on an at-home pregnancy test?

So long as your test is within date and you have followed the storage and usage instructions correctly, home pregnancy tests offer highly accurate results. However, while a positive test result is almost always correct, false negatives are always a possibility.

Can a pregnancy test kit be used twice?

You should not try to reuse a pregnancy test. A test that is already wet from water, urine, or any other moisture, will not give you accurate test results.

Do pregnancy tests work for everyone?

Pregnancy tests work for the overwhelming majority of people. While some fertility medications that contain the hCG hormone may affect the accuracy of test results, other medications, including antibiotics and hormonal birth control, will not affect home pregnancy test results.