Have you been nauseous these past few days, late on your period, and worried you might be pregnant?
Do you have leftover pregnancy tests in the cupboard from God knows when? Are you wondering if you can use them even though they’re expired?
Home pregnancy tests are quick and easy to use. Plus, you can test in the privacy of your home, make lifestyle changes, and find prenatal care as soon as possible if you are indeed pregnant.
But, is an expired test as accurate as a viable one?
Do home pregnancy tests even truly expire?
We will discuss how home pregnancy tests work, when to take one, if and when they expire, and what to expect when using an expired test.
How Do Home Pregnancy Tests Work?
Early in pregnancy, a hormone called human chorionic gonadotropin (hCG) increases rapidly day by day. This hormone is made by the placenta and supports the development of your growing baby.
The test strip in a home pregnancy test contains a chemical which detects the hCG in your urine, confirming whether or not you’re pregnant.
Taking A Home Pregnancy Test
Most doctors recommend waiting until one week after a missed period to take a home pregnancy test. However, some women either don’t experience a missed period or mistake implantation bleeding for a period.
So, if you absolutely cannot wait until you’ve missed your period, the earliest you should take a test is 14 days from the time you think you may have conceived.
You may be experiencing other symptoms of pregnancy during this waiting period, such as:
- Tender, swollen breasts.
- Mood swings.
- Food aversions or cravings.
- Slight bleeding and cramping.
Do Home Pregnancy Tests Expire?
Many women never look for an expiration date, because they don’t even consider the fact, but home pregnancy tests do expire. They all have an expiration date listed on the box or outside packaging of the test.
This date is set at the chemical’s expected shelf life. Once a test is expired, it is essentially no longer valid, as the chemical will be ineffective at detecting hCG in your urine.
When Do They Expire?
This time frame varies, but most typically between two to three years from the time they’re produced. The less expensive tests usually expire sooner, while pricier ones tend to have a longer shelf life.
It is possible for expensive tests to be viable well beyond their expiration date. On the other hand, it’s also possible for cheap tests to no longer work months before, as they might contain low quality chemical reagents. This is why it’s recommended to purchase tests at least six months before their expiry dates.
Are Expired Tests Accurate?
Most home pregnancy tests claim to be 97 to 99 percent accurate when used correctly and taken one week after a missed period (source). But does this hold up for an expired test?
It is possible for a home pregnancy test to be viable after its expiration date. However, most of the time they are more likely to give false results.
Expired pregnancy tests are less likely to detect the pregnancy hormone, as the chemical reactant has degraded, leaving you with a negative result, even if you truly are pregnant. This is called a false-negative result.
Although rare, it’s also possible to get a false-positive result with an expired pregnancy test, especially if the test has been exposed to heat or moisture. A false-positive is when you get a positive result, but are not actually pregnant.
Other Reasons For A False Result
There are several other reasons besides the expiration date why you may receive a false result on a home pregnancy test.
- Taking the test too early: You may not have had enough hCG in your urine yet if you took the test too early. For best results, wait one week after your missed period to take a home pregnancy test.
- User error: User errors like checking the results too soon, misinterpreting the results, and not using midstream urine could potentially lead to a false negative result.
- Urine too diluted: The more dilute your urine is, the lower the concentration of hCG will be. This is why it’s recommended to use more concentrated urine (i.e., your first morning urine).
If you think you might be pregnant even with a false result, wait five to seven days and retake the test. It may also be a good idea to buy a new pregnancy test well ahead of its expiration date.
- Ectopic pregnancy: An ectopic pregnancy is where the fertilized egg implants somewhere other than the uterus, such as the fallopian tubes. It is not a viable pregnancy, and can be dangerous, even fatal, if not treated. If you are experiencing severe abdominal pain or heavy bleeding, see your doctor as soon as possible.
- Miscarriage: It can take weeks for hCG levels to drop after a miscarriage. If you had an early miscarriage, the hCG still in your urine could be giving you a false positive reading.
- Fertility drugs: If you took the test too soon after taking a fertility drug with hCG, you could be experiencing a false positive result.
- User error: Reading the test too soon or too late could give you invalid results. Evaporation lines can also be mistaken for a positive test line. To avoid any misinterpretations, carefully read the manufacturer’s instructions before using a home pregnancy test.
If you think you may be getting false results or are getting mixed results, check with your doctor and get a blood test to confirm conception (source).
Whenever you get a positive result on a home pregnancy test, you should call and schedule your first prenatal appointment. Then, start adjusting your lifestyle to accommodate your growing baby. That positive result could be a false-positive, but it’s more likely you truly are pregnant.
What To Expect With Expired Tests
What happens when you take an expired pregnancy test depends on the quality of the test, how much the chemical reactant has degraded, and whether or not you’re pregnant. You simply cannot rely on an expired home pregnancy test for accurate results.
If you chose to use an expired pregnancy test, be prepared for possible false results. Don’t jump to conclusions, as your results may or may not be accurate. It is best to buy a new one (six months before it’s expiry date) right after, to double check your results.
In my experience, an expired test is considerably more likely to give a false negative result than a false positive result. If you take an expired test and it is positive, you are most likely pregnant.
Editor's Note:Christine Traxler, MD, BS
Home pregnancy tests can give you fast, reliable results. But, to avoid any unnecessary doubts or false results, use a home pregnancy test well before its expiration date.
Most of them typically last two to three years from the manufacturing date. Around the expected expiration date, the chemical reactant in the test strip begins to degrade and loses its ability to detect the hCG hormone. This leaves you with possible false results and worries.
Have you ever used an expired pregnancy test? Were the results accurate? Share your experiences with us in the comments below and be sure to share this post with all of your friends who are trying to conceive.