Medically Approved

5 common pregnancy test mistakes

Woman reading pregnancy test

Peeing on a stick isn’t always as simple as it seems. Here’s how to avoid the pitfalls that could throw off results.

Jennifer Thomas

By Jennifer Thomas

Taking a pregnancy test is pretty foolproof, right? You pee on a stick or insert a stick into a cup of urine, wait a few minutes, and — voilà — you know if you’re pregnant. Well ... not quite. Depending on when you test and how closely you follow the directions, you might get inaccurate results.

That’s not to say that at-home pregnancy tests aren’t accurate. They often work amazingly well. Most manufacturers say their at-home tests are about 99% effective when used as instructed, according to the Cleveland Clinic.

Getting the most accurate results possible depends on a few important factors. A top one is timing. All at-home pregnancy tests look for the so-called pregnancy hormone hCG in urine. But some tests are more sensitive than others. Test too soon after becoming pregnant and you might not have levels high enough for the test to catch.

Fortunately, many at-home pregnancy test mistakes can be prevented. Here are 5 of the most common ones and how to avoid them.

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Mistake #1: Not reading the directions

Are you the kind of person who sees directions as suggestions rather than a blueprint? Then this one’s for you. With a pregnancy test, it’s very important to read the directions. All pregnancy tests measure hCG, but they don’t all work exactly the same way.

Each requires a certain amount of urine. That’s why some tests ask you to pee directly onto a stick, while others have you dip the stick in a cup of urine. And it’s why they’re specific about how long to hold the absorbent part of the stick in your stream (or in a cup). Not following these directions can lead to inaccurate results.

While you’re looking at the box, take a peek at the expiration date. Tests collecting dust in your closet for years probably won’t be as accurate as ones fresh off store shelves.

(When you’re trying to get pregnant, an ovulation test such as this one can help you get your timing right.)

Mistake #2: Testing too early

Testing too soon after sex is usually the biggest mistake people make, says Robin Watkins. She’s a certified nurse midwife and director of health care at Power to Decide. Many pregnancy test manufacturers say their tests are more than 99% accurate from the day of your first missed period. But that day isn’t always obvious.

For many women, their periods don’t start on the same day (or week) every month. The U.S. Food and Drug Administration (FDA) estimates that as many as 20% of women won’t be able to detect their pregnancy on the first day of their missed period.

There’s nothing wrong with testing on the first day you’re late. But the FDA recommends waiting 1 to 2 weeks after your first missed period for the most reliable results.

“If you think you might be pregnant but got a negative test result, it might be too early,” Watkins says. “Wait a few days and take another test, or check in with a health care provider.”

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Mistake #3: Using diluted urine

Gulping down several glasses of water before you take a pregnancy test isn’t the best idea.

Many people think this will increase the volume of urine, but it can dilute the hCG levels, according to the Cleveland Clinic.

Instead, take a pregnancy test when you first go to the bathroom in the morning. That’s when you’ll have a full bladder of nondiluted urine. “Urine can be more concentrated first thing in the morning, so you may get a positive test a bit sooner if you’re checking then,” Watkins says.

Mistake #4: Looking too soon (or too late)

We get it: It’s tempting to peek at your pregnancy test results before the timer buzzes. Still, it’s important to read the results in the timeframe listed in your test’s directions. (Yes, those pesky directions again.) Looking too soon and ditching the test before time’s up could lead to a false negative.

On the flip side, looking too late could lead to a false positive. That’s especially important with nondigital line tests. Waiting too long can sometimes cause a faint, colorless evaporation line to appear when the urine dries. While lines without color aren’t a sign of pregnancy, they can be confusing, Watkins says.

Mistake #5: Misreading the results

Don’t feel bad if you’re confused about what your pregnancy test tells you. There are entire internet forums dedicated to deciphering the results of people’s nondigital pregnancy tests. Trying to figure out if a line is a line or a plus is a plus can be tough.

Because of that, you might do better with a digital test that says “pregnant” or “not pregnant” when the results are ready. These tests aren’t more accurate than nondigital ones, but they can take the guesswork out of reading lines or signs.

If you get a result you’re just not sure about, wait and test again. And if things are still clear as mud, Watkins suggests talking to your health care provider about getting a blood test. It can detect lower levels of hCG than a urine test.

All in all, at-home pregnancy tests are pretty reliable. If you get a positive test, touch base with your health care provider as soon as possible. They’ll be able to confirm the results and make sure you and your baby are as healthy as can be.

Another thing that’s reliable? Our free mobile app. With our coupon finder and pharmacy map, we’ll help you make sure you’re getting the best price possible for your prescription medications.

Additional sources
What pregnancy tests are and how they work:
Cleveland Clinic
The basics of at-home pregnancy tests: U.S. Food and Drug Administration