Did you know pregnancy tests have an expiration date?

Most things have an expiration date but one you might not think of is pregnancy tests

Whether you're hoping to get pregnant or not, it's an important thing to check before you use one or else you might not get an accurate understanding of what's happening to your body.

Before we get into all of that, it's important to know how pregnancy tests work.

How do they work?

While we all know that most pregnancy tests involve urinating on a stick, why do we actually have to do it?

Pregnancy tests detect the hormone human chorionic gonadotropin (hCG) in a woman's urine.

This hormone is produced by cells that form the placenta after a fertilised egg implants in the uterus and your body starts producing hCG about 12 days after fertilisation occurs.

When you take a test you want to make sure the control line appears, or a digital version of it, to know that it's functioning properly.

Also, be aware the most accurate reading you'll get is after a missed period.

Expiration date

The typical shelf life of a pregnancy test depends on the brand.

According to Stephanie Hack, M.D., OB-GYN and founder of Lady Parts Doctor, the shelf life of a pregnancy test is typically two to three years after the manufacture date for both the digital and non-digital types.

So be aware that some tests have been sitting on a shelf in stores for longer than you realise so their expiration date may be sooner than you think.

How accurate are expired tests

After the pregnancy test expires, it's usually not as effective at detecting the hCG hormone, as the chemicals used may degrade or evaporate over time.

This can cause false negative pregnancy tests, which happen when the test reads negative, but you're actually pregnant.

False positives are also possible but are less likely.

Though they may still give a correct result in some circumstances, there is a greater likelihood won't.

Where can I find the expiration date?

Again, it varies from brand to brand but as an example, a Clearblue test will have it printed on both the bottom of the box and the foil wrapper.

You should always check the date for using a pregnancy test but especially if it's one you've had sitting in a bathroom cabinet for a while.