Home pregnancy tests contain a special strip that detects levels of a particular hormone called hCG in your urine.
However, as it reaches its expiration date, a pregnancy test can be less effective in detecting hCG.
You might be wondering if you can take an expired pregnancy test (or one that’s very close to its expiration date).
In this guide from PregnancyResource.org, we explain why pregnancy tests expire, why you shouldn’t take an expired pregnancy test, and what you can do to get the most accurate pregnancy test results.
Do Pregnancy Tests Expire?
A little-known fact is that pregnancy tests are regulated by the Food and Drug Administration (FDA). One result of this regulation is that all home pregnancy tests are required to have an expiration date.
Home pregnancy tests — even the digital versions — expire within one to two years.
You can find the expiration date on the box of your home pregnancy testing kit.
If you bought a box of multiple pregnancy tests, then you should also see the expiration date on each individual wrapper.
Why Do Pregnancy Tests Expire?
To explain why home pregnancy tests expire, let’s go over how pregnancy tests work.
Home pregnancy tests detect a special hormone called human chorionic gonadotropin (hCG) in your urine. This hormone is produced shortly after a fertilized egg implants into the uterus.
This process takes about 6-12 days after conception.
Everyone has hCG in small amounts whether they’re pregnant or not. However, shortly after implantation, during the very early pregnancy stage, levels of this hormone begin to double every 48 hours.
This is done to help thicken the endometrial lining and prepare the body for carrying a baby.
A pregnancy test has a small strip with antibodies that detect the hCG hormone. When someone who’s pregnant places their urine on the testing strip, the antibodies react with hCG to produce a chemical change.
Depending on the home test, this usually results in an extra colored line, a second faint line, a plus sign, or digitally-displayed text that says “pregnant.”
However, the closer the test gets to its expiration date, the less effective these antibodies become, and your chances for an accurate reading decrease.
As the expiration date approaches, it becomes less and less likely that the test will be sensitive enough to produce a chemical change in response to increasing hCG levels.
This can give off a “false negative” result (one that says someone isn’t pregnant when they really are) that can cause a lot of hiccups.
There are other reasons why some women may get a false negative result, which you can learn about here!
How Long Do Pregnancy Tests Last?
Typically, pregnancy tests last anywhere from one to two years.
Some high-quality ultra-sensitive pregnancy tests can even have a shelf life as long as three years. The more sensitive a test is, the less hCG it needs to produce an accurate result.
Even if it becomes less effective in the future, it can still pick up on some hCG in your urine.
That said, manufacturers will tell you not to use their tests after they expire. In many cases, the testing strip won’t be able to pick up increased hCG levels.
With that, it’s best practice to check the expiration date at the drugstore before you purchase your test as well.
If you use an expired pregnancy test, you are more likely to get a false negative result, which can make you miss out on important prenatal care.
3 Things To Note About Pregnancy Tests and Expiration
You know the importance of not taking a pregnancy test too early or not drinking too much water (as this can dilute hCG levels), but to get the most accurate results, it’s also essential to choose the right pregnancy test.
1. Expiration Date
Each pregnancy test has its own expiration date, with 1-3 years being the range of possible shelf lives.
Try not to assume when a pregnancy test expires. Instead, look at the expiration date on the packaging, and avoid using a test kit with a close expiration date.
2. Storage Temperature
You may have an old pregnancy test that’s not (yet) expired. However, the way it was stored can affect how and if it works.
A pregnancy test should be stored at room temperature away from direct sunlight.
However, if it was lying around in hot and humid conditions — or, on the opposite spectrum, in the freezing cold — then it may not be as effective.
It’s better to be safe than sorry and just buy a new pregnancy test. If you buy more than several for future use, make sure to store it in dry conditions at room temperature.
3. How Soon You Take It
Some pregnancy tests can be close to their expiration date, which means they’re not as sensitive to hCG levels in your urine, but the timing of other things matters, too.
If you take the test really early in your pregnancy, such as within just a week after conception, the test may not pick up on it.
However, even an expired pregnancy test can detect some levels of hCG.
In general, the longer you wait to take a pregnancy test, the more time your body will have to build up the pregnancy hormone hCG, basically giving a pregnancy test more to work with.
If you’re taking a digital pregnancy test that’s close to its expiration date, keep in mind that it’s best to wait a little time after having unprotected sex.
For the most accurate results, take the test after your first missed period.
Home pregnancy tests are regulated by the FDA, and they are required to come with an expiration date.
If you’re taking an expired pregnancy test, you may get a false negative result, which tells you that you’re not pregnant — when you really are.
For the most accurate results, check the expiration date on your pregnancy test and make sure that it’s stored at room temperature. It also helps to wait until after your first missed period to let hCG build up in your body.
If you receive a surprisingly positive test, or a false positive result but you feel like you may be pregnant, you can either wait a little longer and test again, or schedule a visit with your women’s health doctor.
Your OB-FYN will likely do a blood test and urine test to check for pregnancy, as well as look for signs of an ectopic pregnancy.
References and Sources:
Bridget Reed is a Tampa-based content development manager, writer, and editor at GR0; specializing in content related to varying fields including medicine, health, and small businesses. Bridget went to St. Petersburg College and majored in Management and Organizational Leadership.
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