How to Choose the Best Pregnancy Test for You

It’s a big moment you’ll never forget. Standing in the bathroom, anxiously staring at a little plastic stick and waiting, waiting, waiting until it gives you the news: You’re pregnant!

First introduced in the U.S. in the 1970s, home pregnancy tests have become increasingly reliable and early-detecting: Today, there are tests that claim they can tell you if you are pregnant as many as six days before a missed period. Keep in mind, however, that not every pregnancy is the same, and therefore not every test will be as accurate at any given time for any given woman. (More on that below.)

How They Work: All home pregnancy tests are based on detecting the presence in urine of the hormone hCG, which your body begins producing around the time a fertilized egg implants in the uterus. For most women, that happens around six days after conception, before you’ll miss your period—and this is how some kits can promise accuracy that early on. But experts say that for about 10% of women, implantation (and thus the production of hCG) doesn’t happen until after a missed period And that’s how many false negatives happen: It’s too early for the hormone to be detected in your body.

Strength in Numbers: Buy a multi-pack. You’ll want to have another test handy if the first result is unclear. If it comes out negative, but you then miss your period, you’ll want to take the test again.And if it’s positive, you may still want to take another one, just to double, triple and quadruple check. Usually, doctors won't schedule you for an appointment until you're eight weeks along—which can feel like an eternity—so taking an extra test at home in the meantime won't hurt.

Reliability: Some home pregnancy tests claim to be 99% accurate. But keep in mind there is always room for error—perhaps not enough urine was used, or you were overhydrated, or not enough time passed before checking the results. And remember, the early-results kits aren’t fool-proof. A week after your missed period is the general rule of thumb for a reliable reading.

If you get a positive result, you should make an appointment with your OB/GYN to confirm the pregnancy and begin prenatal care. When you visit your doctor, an ultrasound will reveal if are officially pregnant—and give you your first glimpse of a heartbeat.

Test in the Morning: You’ve probably heard it before: Always take a home pregnancy test first thing when you wake up. But is this really true? If so, why? The hCG levels are very low at the beginning of a pregnancy, so even if you’re using an extremely sensitive early-results test, you want to make sure that the urine sample you collect is concentrated enough for the hormone to be detected. Taking the test in the morning, hours after you last went to the bathroom or consumed liquids, will ensure that your urine sample isn’t diluted. Of course, as your pregnancy progresses, the hormone level goes up rapidly, so for most women, by a week after a missed period, the hCG will be detectable by most home pregnancy tests at any time of the day.

Check the Expiration Date: These tests use a chemical that reacts with hCG. When that chemical becomes less effective, the tests are considered inaccurate and expired. Generally speaking, the tests have a shelf life of two to three years after they're manufactured. If you want to be sure you're getting the most accurate reading, make sure you use new tests and not ones you found at the back of your medicine cabinet.

Other Signs: While tests will give you a plus or minus symbol, you may see your own indications of early pregnancy—and feel the symptoms. Some women experience cramping and spotting (or implantation bleeding), which could potentially be confused for a light period. Fatigue could also set in early on, as well as nausea, though every woman experiences symptoms differently and to varying degrees.

Spread the News: Once you’re ready to tell the world, check out these fun ways other parents-to-be have shared the good pregnancy news with their friends and family.

This guide will show you the differences between the types of pregnancy tests available now—as well as other products you can use when you’re trying to conceive.