When should you get a pregnancy test

There are two main types of pregnancy tests: urine and blood tests.
Take a home urine test after your next missed period — anywhere from 14 to 18 days after conception.
Blood tests are more sensitive and can tell you if you're pregnant 6 to 14 days after conception.

You have two options when it comes time to see if you have a baby on board.

Table of Contents Show

When should you take a blood pregnancy test?
When should you take a home pregnancy test?
How accurate are pregnancy tests?
Insider's takeaway
When should I take a home pregnancy test?
Are there different types of home pregnancy tests?
How accurate are home pregnancy tests?
Could medications interfere with test results?
Could a positive result be wrong?
Could a negative result be wrong?
What happens next?
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The most common is an at-home urine pregnancy test, available over the counter, though you can take a urine pregnancy test at a medical clinic. Another option is a blood test performed at a medical clinic.

"Both tests check for a hormone called human chorionic gonadotropin, or hCG," says Crystal Newby, MD, of Kansas City Ob-Gyn. "This hormone is produced after a fertilized egg attaches to the wall of your uterus."

The egg typically attaches 6 days after fertilization, at which point, hCG levels in your blood and urine will increase for the next 6 to 10 weeks. Once hCG levels are high enough, you can expect an accurate reading, but not before then.

When should you take a blood pregnancy test?

Depending on a woman's cycle, a blood test can detect pregnancy between 6 and 14 days after conception.

Blood tests for pregnancy are more sensitive to hCG than home pregnancy tests. They can detect this hormone in low quantities and tell you if you're pregnant sooner than a home test.

While blood tests can provide results sooner than home pregnancy tests, they are usually more expensive and take longer to provide results because the blood must be sent to a lab for analysis.

If the lab is in-house then it will take a few hours. But if the lab is at a different location, it could take several days to learn the results.

When should you take a home pregnancy test?

Most home pregnancy tests advise you to take the test after you miss your next period. If you have a standard 28-day cycle, you'll be most fertile two to three weeks before your period.

So if you get pregnant during that fertility window, you'll need to wait at least 14 to 18 days after conception to take a home pregnancy test.

If you get a negative result and suspect you're pregnant, check the instructions on the box. Home pregnancy tests typically recommend retaking the test 5 to 7 days later, when the hCG levels in your body will be higher.

This type of result is called a "false negative." Sometimes you can receive a false negative result if you take a pregnancy test too soon when your hCG levels are too low for the test to detect them accurately.

Moreover, recent miscarriages, fertility drugs, and rare hCG secreting tumors can interfere with the results of at-home urine tests. If you receive conflicting results after taking a home pregnancy test multiple times, doctors recommend a blood test.

How accurate are pregnancy tests?

Blood pregnancy tests are considered by doctors to be 99% accurate. Quantitative blood tests (also called beta hCG tests) are the most accurate blood tests and can help doctors tell the exact age of the fetus and play a role in detecting any abnormalities.

If you follow directions, home pregnancy tests are an estimated 97% to 99% accurate. If you perform a urine pregnancy test in a lab setting, like at your doctor's office, the accuracy will be closer to 99%. It's important to make sure that you check the expiration date on your home test, as it can affect the accuracy of the results.

After taking either a blood or urine test, it's important to confirm the pregnancy with an early ultrasound.

Insider's takeaway

Home pregnancy tests can provide results faster and be more convenient than a blood test. But you'll probably have to wait longer to receive accurate results.

You can expect accurate results from a blood pregnancy test as soon as 6 to 14 days after conception. Because the test must be analyzed in a lab, it could take up to several days to get the results.

To get the most accurate reading from a home urine test, wait until your missed period. This can come anywhere between 14 to 18 days after conception. If you get a negative result, you can try taking a home test again in 5 to 7 days to see if you have higher amounts of detectable hCG in your body.

Blood tests are considered to be 99% accurate, while home pregnancy tests are around 97% to 99% accurate. Regardless, you should confirm your results by getting an ultrasound.

Denice Rackley is a freelance writer for Insider.

When should I take a home pregnancy test?

Many home pregnancy tests claim to be accurate as early as the first day of a missed period — or even before. You're likely to get more accurate results, however, if you wait until after the first day of your missed period.

Why wait? Shortly after a fertilized egg attaches to your uterine lining (implantation), the placenta forms and produces the hormone human chorionic gonadotropin (HCG). This hormone enters your bloodstream and urine.

During early pregnancy, the HCG concentration increases rapidly — doubling every two to three days. The earlier you take the home pregnancy test, the harder it might be for the test to detect HCG.

Keep in mind that the timing of your ovulation might vary from month to month, and the fertilized egg can implant in the uterus at different times. This can affect the timing of HCG production and when it can be detected. If your periods are irregular, you might miscalculate when your period is due.

If it's important to confirm your pregnancy right away and depending on how far along you are in your pregnancy, your health care provider might recommend that you have an ultrasound, repeat a urine test at a lab or have a blood test to measure your HCG levels.

Are there different types of home pregnancy tests?

With most tests, you place the end of a dipstick in your urine stream or dip the dipstick in a container of collected urine. A few minutes later, the dipstick reveals the test result — often as a plus or a minus sign, one line or two lines, or the words "pregnant" or "not pregnant" on a strip or screen.

Follow the test instructions for how long to wait before checking results — usually two or more minutes. Most tests also have a control indicator — a line or symbol that appears in the result window. If the line or symbol doesn't appear, then the test isn't working properly. Try again with another test.

Some home pregnancy tests are more sensitive than others. In other words, the amount of HCG needed to be detected in the urine to produce a positive test result is lower in some tests.

Always check the test's expiration date and read the instructions carefully before you take the test.

How accurate are home pregnancy tests?

Many home pregnancy tests claim to be 99 percent accurate. However, home pregnancy tests differ in the ability to diagnose pregnancy in women who have recently missed a period. If you have a negative test but think you might be pregnant, repeat the test one week after your missed period or talk to your health care provider.

Could medications interfere with test results?

Fertility drugs or other medications that contain HCG might interfere with home pregnancy test results. However, most medications, including antibiotics and birth control pills, don't affect the accuracy of home pregnancy tests.

Could a positive result be wrong?

Although rare, it's possible to get a positive result from a home pregnancy test when you're not actually pregnant. This is known as a false-positive.

A false-positive might happen if you had a pregnancy loss soon after the fertilized egg attached to your uterine lining (biochemical pregnancy) or you take a pregnancy test too soon after taking a fertility drug that contains HCG. An ectopic pregnancy, menopause or problems with your ovaries also might contribute to misleading test results.

Could a negative result be wrong?

It's possible to get a negative result from a home pregnancy test when you're actually pregnant. This is known as a false-negative. You might get a false-negative if you:

Take the test too early. The earlier after a missed period that you take a home pregnancy test, the harder it is for the test to detect HCG. For the most accurate results, repeat the test one week after a missed period. If you can't wait that long, ask your health care provider for a blood test.
Check test results too soon. Give the test time to work. Consider setting a timer according to the package instructions.
Use diluted urine. For the most accurate results, take the test first thing in the morning — when your urine is the most concentrated.

What happens next?

Based on your test results, consider taking the following steps:

Your home pregnancy test is positive, or you've taken a few home pregnancy tests and gotten mixed results. Make an appointment with your health care provider. You might need a blood test or ultrasound to confirm your pregnancy. The sooner your pregnancy is confirmed, the sooner you can begin prenatal care.
Your home pregnancy test is negative. If your period doesn't begin, repeat the test in a few days or one week — especially if you took the test before or shortly after a missed period.
You continue to get negative test results, but your period doesn't begin or you still think you might be pregnant. Check with your health care provider. Many factors can lead to missed menstrual periods (amenorrhea), including thyroid disorders, low body weight, problems with your ovaries, excessive exercise and stress. If you're not pregnant, your health care provider can help you get your menstrual cycle back on track.

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Feb. 24, 2021

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