At-home pregnancy tests

home pregnancy

Home pregnancy tests work by detecting the presence of a hormone called hCG in your urine. Some at-home pregnancy tests claim they’re sensitive enough to give a positive result as early as five days before your next period. But you’re more likely to get an accurate result (and avoid a false negative) if you wait until the first day of your missed period.

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How do home pregnancy tests work?

All home pregnancy tests measure the amount of a specific hormone known as human chorionic gonadotropin (hCG) in your urine. When the embryo starts to implant in the lining of your uterus, as early as six days after conception, cells that will later develop into the placenta begin to produce hCG.

As the placenta grows, the amount of hCG in your body doubles every two days or so during the first few weeks. When hCG levels are high enough, the hormone enters the bloodstream. That’s when it starts to show up in the blood and urine. If the home pregnancy test detects enough hCG in your urine, it gives you a positive result.

Some tests are more sensitive than others. But in general, it’s easier for any home pregnancy test to pick up hCG in the urine when you’re 4 weeks pregnant (when there’s more hCG) versus 6 days after fertilization (when there’s a trace amount of hCG at best).

The best way to tell if a test is sensitive enough to pick up the smaller amounts is to read the fine print. Some urine pregnancy tests can detect lower levels of hCG. If you’re wanting to test early, before you miss a period, check the package insert to learn more about how much hCG needs to be present in your urine to detect a pregnancy.

How to use an at-home pregnancy test

For best results when using a home pregnancy test:

  • Make sure the test is up to date. Check the expiration date on the package, especially if you’ve had it for a while. If you’ve been storing the test in the bathroom, the humidity may have ruined it. Better to throw it away and get a new one.
  • Test first thing in the morning. Your urine is most concentrated when you first get up. If you’re pregnant, hCG levels will be higher too. That makes it easier for the at-home test to spot it.
  • Read the directions carefully. Different brands have different instructions. With some home tests you urinate in a cup and then use the dropper to place a small sample in the testing well. With others, you can pee directly onto the strip or stick. And some let you do either.
  • Wait 5 minutes to check. You get the most accurate results if you wait up to 5 minutes, though this can vary by brand. Read the package instructions to learn exactly how long you’ll need to wait to confirm a negative or positive result.

Different tests reveal the results in different ways too. Some show pink or blue lines on the test strip, while others have a red plus or minus sign in a window. Digital tests give results in words (“You’re pregnant”). Most have a control indicator (often a second line or symbol) that tells you whether the test is valid.

If the control indicator doesn’t show up properly, the test is probably faulty. If this happens, call the manufacturer and see if they’ll send you a new one. Also call the company if you have questions about how to use the test.

If the test shows a negative or a faintly positive result, wait another few days and try again if you still haven’t gotten your period. Maybe you ovulated later in your cycle than you thought and took the test too early to get a positive result.

One negative result doesn’t necessarily mean you’re not pregnant. Every woman produces different amounts of hCG and it’s not even the same for each pregnancy. If you suspect that you’re pregnant (say, you’re having early pregnancy symptoms) and still have a negative test, take another home pregnancy test in a week if you still haven’t gotten your period.

If you still haven’t gotten either your period or a positive result two weeks or so after you would expect it, reach out to your provider.

When can I take an at-home pregnancy test?

At-home pregnancy tests are getting better and better. But you’re still more likely to get the most accurate results if you wait to take a pregnancy test until the morning of your expected period. Waiting a few more days after that may provide an even more accurate result.

Some home pregnancy tests claim they’re sensitive enough to give you a positive result as early as five days before your next period. And some women will have produced enough hCG to get a positive result at that point. But, once again, every pregnancy is different.

If you’re eager (or anxious) to know if you’re pregnant, go ahead and do the test 10 or 12 days after you think you’ve conceived. If you get a negative result, no problem. Wait a week and test again if you still haven’t gotten your period.

How accurate are home pregnancy tests?

At-home pregnancy tests are 99 percent accurate. But you can still get what are called false negatives or false positives.

A false negative is when you’re pregnant but the test results show up negative. Sometimes you get a faint line on the home pregnancy test, so the result is unclear. These things usually happen if you take the test too soon, before your hCG levels are high enough. If you get a faint line on a pregnancy test, wait a few days and test again.

A false positive pregnancy test means that you get a positive result but aren’t pregnant. This doesn’t happen very often, except for in the following circumstances:

  • You’ve had a miscarriage or terminated a pregnancy in the past eight weeks, or have a molar pregnancy.
  • You’ve taken a fertility drug with hCG (used to induce ovulation in fertility treatments).
  • You have a rare medical condition, such as an hCG-secreting tumor.
  • You’re using an expired or faulty test.
  • You’re going through perimenopause or menopause.

If you have a positive result and then get your period soon after, you may have had what’s called a chemical pregnancy. This means the embryo implanted in your uterus and developed just enough to start producing detectable levels of hCG, but then it stopped developing. This is most commonly caused by a genetic abnormality of the embryo.

An ectopic pregnancy can also result in a positive pregnancy test, even though these pregnancies often show slower rises in hCG.

No matter what result you get from a pregnancy test, call your healthcare provider right away if you:

  • Feel dizzy or faint
  • Have abdominal pain (especially a sharp or stabbing pain in your abdomen or on one side of your pelvis
  • Have abnormal bleeding

These could be signs of a miscarriage or ectopic pregnancy.

What to do if you get a positive home pregnancy test

Some women take more than one home pregnancy test (or several) just to be sure – but that’s not really necessary. Once you’ve gotten a positive pregnancy test, call your healthcare provider to set up a prenatal visit or to discuss your options if you’re not sure about continuing the pregnancy.

If you don’t already have a family doctor, ob-gyn, or midwife who can provide prenatal care, do some research to see who’s covered by your insurance, and ask for recommendations.

Doctors typically schedule the first prenatal visit when you’re about 8 weeks pregnant. But some providers will see you sooner, especially if you have a medical condition or have had problems with a pregnancy in the past. It’s especially important to see your provider sooner if you’re having nausea and vomiting, vaginal bleeding, or abdominal pain.

Will you need a blood test to confirm your pregnancy?

Not necessarily. To make sure you’re pregnant, most healthcare providers use a urine pregnancy test, just like your at-home pregnancy test . But your provider may use a blood test instead. Just note: It may take anywhere from an hour to a day or more to get the results.

There are two types of pregnancy blood tests:

  • A qualitative hCG blood test just shows whether there is hCG in your blood. The results return as “positive” or “negative.” You usually get the results in about the same time you would with a urine test.
  • A quantitative blood test (beta hCG test or serum test) measures the exact amount of hCG in your blood. The results return as a number. This test is very accurate. It can detect hCG as early as six to eight days after ovulation, or about a week before your period is due. It takes longer to get results from a quantitative blood test, though.

Again, your provider may not give you a blood test. Oftentimes, a positive home pregnancy test is enough to get started with the prenatal care you need.

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