Pregnancy Test Basics: When to Take Them, Getting the Results, and More

Woman holding a pregnancy test

Have you missed a period or noticed any other signs of pregnancy? Then perhaps you’re wondering whether or not to take a pregnancy test! Learn all about when to take a test, how pregnancy tests work, and how accurate they are, plus how soon a pregnancy can be detected, how to read a pregnancy test, and more.

How Do Pregnancy Tests Work?

Pregnancy tests work by detecting a hormone known as hCG (human chorionic gonadotropin). Often called the “pregnancy hormone,” hCG is produced by the developing placenta after a fertilized egg implants in the uterus lining following conception. Your body will continue to produce hCG at very high levels in the first three to four months of pregnancy. It signals your body to sustain the pregnancy and can be detected by pregnancy tests in your urine and blood.

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What Types of Pregnancy Tests Are There?

Two types of pregnancy tests can detect the presence of hCG: urine tests and blood tests. The typical home pregnancy test you can get at the drugstore tests your urine, whereas a healthcare provider must conduct a blood test.

A Urine Pregnancy Test

A home pregnancy test uses your urine to detect hCG. If you’re wondering where to buy pregnancy tests like these, you can get one at any drugstore, grocery store, or community clinic, or from your healthcare provider. Once you have one, your next question might be how to use a pregnancy test. The process for taking a home pregnancy test is relatively straightforward; here’s what to do:

  1. Read the instructions. Different home pregnancy test brands may have slightly different directions. For example, how long to pee or how long to wait for results may vary from brand to brand.

  2. Remove the stick (and cup) from the packaging. What does a pregnancy test look like? Home pregnancy tests come in stick form. With some, you’ll pee directly onto the end of the stick, whereas with others, you’ll dip the stick into a small cup of your urine.

  3. Pee. Depending on the instructions, you’ll pee directly on the stick—a prepared chemical strip—or dip it into a urine cup.

  4. Wait. All home pregnancy tests work by detecting hCG in your urine, but the instructions and wait times will vary among brands. Some brands are more sensitive than others.

  5. Read the results. Classic tests reveal the news with signs and lines. A plus sign or two lines usually indicates a positive pregnancy test. Digital pregnancy tests spell out the news with words like “pregnant” if positive or “not pregnant” if negative.

You can take a urine pregnancy test in your healthcare provider’s office or at home. In the office setting, the provider can ensure a correctly performed and give you the results.

A Pregnancy Blood Test

Only a healthcare provider or clinician can perform a pregnancy blood test. A blood test won’t offer an immediate result like with a urine test—it can take from a few hours to more than a day—but it’s more sensitive and accurate. A common question is how soon or how early you can take a pregnancy test. One perk about pregnancy blood tests is that they work during early pregnancy. So, how soon can a blood test detect pregnancy after conception? They work as early as 9 to 12 days after conceiving! There are two types of pregnancy blood tests:

  • Quantitative blood test. Also known as a beta hCG test, this test measures the exact amount of hCG in your blood.

  • Qualitative test. This test indicates if the hormone is present in the blood or not.

What pregnancy test is the most accurate? Both types of pregnancy blood tests can indicate pregnancy early and more accurately than at-home urine tests.

How Accurate Are Pregnancy Tests?

Most home pregnancy tests claim to have an accuracy rate of 99 percent; however, the result you receive can depend on various factors, such as:

  • When you take the test. Do you have to take a pregnancy test in the morning? The best time to take a pregnancy test is first thing in the morning when hCG levels are more concentrated. It’s also a good idea to wait until one week after your missed period before testing, when a home pregnancy test is most accurate.

  • The expiration date of your test. Do pregnancy tests expire? Yes, they do! Make sure your test is not past its expiration date, as this can affect the accuracy of the results.

  • Your fluid intake. Did you know that drinking too much water before taking the test can dilute the hCG levels in your urine? That’s another reason why it’s best to take a test upon waking up and before drinking any fluids.

  • How you perform the test. It’s important to follow the test instructions precisely, as this can also affect the results you get.

  • The brand of the test. Some brands will be more sensitive than others.

  • If you’re taking medications with hCG in them. Although most medications won’t affect a home pregnancy test, taking fertility drugs with hCG can impact your results.

Can You Get a False Negative Result?

Yes, it’s possible to get a false negative result on your pregnancy test when you are actually pregnant. What can cause a false negative pregnancy test? False negatives typically occur if

  • you take the test too soon (before one week after your missed period)

  • your urine is too diluted from drinking liquids

  • you don’t wait long enough for the results.

That last point begs the question how soon will a pregnancy test read positive or negative? Depending on the test and its instructions, you may need to wait as long as 10 minutes to get the most accurate result. Follow the instructions on your test closely and give the test time to work. If you’re feeling anxious or excited, you may even want to set a timer and find a distraction, so you don’t look too soon!

Can You Get a False-Positive Result?

It’s possible to get a false-positive result on a home pregnancy test, meaning that the test shows you’re pregnant when you’re not. This outcome is rare, however. What can cause a false positive pregnancy test? You could get this result if you’re taking a fertility drug containing hCG, for example, or if you simply take the test incorrectly.

When Should You Take a Pregnancy Test?

We’ve already mentioned the best time to take a pregnancy test above, but this is such a common question that it’s worth emphasizing! The best time to take a pregnancy test is a week after your missed period. This time is when the results will be more accurate. You can take a test earlier, but it’s better to wait until after your first missed period, as you might not be producing enough hCG before then. But, can you take a pregnancy test while on your period? How long after sex can you take a pregnancy test? Again, these are very common questions, but remember that your body only produces hCG after the fertilized egg implants itself in the lining of your uterus and the placenta starts to form, which might cause some light implantation bleeding. Your hCG levels will double every two to three days during the first few weeks of pregnancy, which is why it’s a good idea to wait to take a pregnancy test. In the meantime, if you’re wondering whether you’re pregnant or not, you might want to look out for some early signs of pregnancy, which may include

If you suspect you may be pregnant, you can test your knowledge with our “Know Your Early Signs of Pregnancy” quiz below:

What to Do After a Positive Pregnancy Test

Once you learn the news, make an appointment with your healthcare provider. If you want to know how far along you are in your pregnancy, check out our Due Date Calculator.

The Bottom Line

If you’ve been trying to conceive, missed your period, or started to notice some of those typical pregnancy symptoms, you probably want to know whether or not you’re pregnant. Home pregnancy tests, which work by detecting levels of hCG in your urine, are a great way to confirm that you're pregnant. For the most accurate results, it’s best to wait at least a week after your first missed period or opt for a pregnancy blood test by your healthcare provider, which can detect pregnancy earlier. There’s a lot of fascinating science that goes into pregnancy tests, but we hope this basic guide helps you understand how at-home urine tests or blood tests work, when you should take one, and how accurate they are. If you received a positive result and are now starting to prepare for a new baby, don’t forget that the Pampers Club app rewards you for all those diapers and wipes purchases!