This post covers the ins and outs of taking pregnancy tests, including when to take them, and how to get the most accurate results.

All pregnancy tests measure the same thing: urinary levels of human chorionic gonadotropin (hCG), a placenta-produced hormone of pregnancy. HCG finds its way into your bloodstream and urine almost immediately after an embryo implants in the uterus. However, it does take some time before concentrations are high enough to be detected.

When to take a pregnancy test

It’s best to wait until roughly 20 days after fertilization so that hCG levels rise enough to be detectable by the test. Most tests now are very sensitive so you could take one as soon as your period is due but bear in mind, it may be a bit early yet so a negative test doesn’t really tell you anything! Ideally, you should wait until about a week after your period would have been due. At this stage, a test will be able to detect hCG and indicate whether you’re pregnant or not via a second line, a plus sign, or a digital ‘yes’ – depending on your test kit.

How to take a pregnancy test

While the exact details of how to take a pregnancy test can vary from brand to brand, they have a lot in common. Read the instructions carefully before use to ensure you are complying with the specific method associated with your test. You’ll typically either be asked to hold the test stick in your stream of urine for a few seconds, or collect your urine in a cup and dip the stick into it.  Further, pregnancy tests are likely the simplest ones you’ll ever take.

Here are a few things you can do to improve their accuracy:

Avoid drinking large quantities of liquid in advance of taking the test as it can dilute hCG levels.

Check the expiration date before using the test.

Follow the home pregnancy test package directions for how long you should wait and what signals correspond with positive and negative results.

If the test comes back positive, that means there’s hCG in your urine- congratulations, you’re pregnant!