What time of day is a pregnancy test most accurate

When you’re waiting on the results of a pregnancy test, minutes can feel like hours. Test too early, however, and you risk the chance of an inaccurate result. To help ensure your test accuracy, there are some guidelines you should follow—like knowing where you are in your menstrual cycle or when you last ovulated.

Here’s everything you need to know about pregnancy tests, including how they work, when to take one for the most accurate result and symptoms that could signal it’s time to take a test.

How Does A Pregnancy Test Work?

Pregnancy tests detect human chorionic gonadotropin (HCG), commonly known as “the pregnancy hormone.” This hormone is generated from the placenta, an organ that connects the fetus to the mother. It begins to form and protect the egg once it’s implanted along the uterine wall, signaling pregnancy has begun. At first, HCG levels are low, but they increase at the beginning of the pregnancy before leveling off.

As HCG levels increase—often doubling every three days until reaching their peak within the first 8 to 11 weeks of pregnancy—they can be detected in both blood tests (conducted at a doctor’s office) and urine tests (most often taken at home).

There are three types of at-home tests: strip, cassette and midstream. Strip tests require you to urinate into a cup and place the test strip directly into the urine. Cassette tests require you to urinate into a cup and then place drops of urine directly onto the test stick. Finally, midstream tests require you to urinate directly onto the test stick.

Your HCG levels must reach 25 milliInternational units (mIU) per millimeter (mL) to indicate a positive result—which often happens within 3 to 5 weeks after your last menstrual cycle. At-home pregnancy tests detect these HCG levels and most often reveal lines or a reading of “Pregnant” to indicate a positive result, depending on the type of test you take.

“Most home (urine) pregnancy tests detect HCG levels of 20 (mIU) or greater,” says Kelly Culwell, M.D.—known professionally as “Dr. Lady Doctor”—a board-certified OB-GYN and a previous medical officer for the World Health Organization in Geneva, Switzerland. “Blood tests detect HCG levels of 2 (mIU) or greater, so a blood test might be positive before a urine test is.”

While a typical urine test will show positive results at about 20 to 25 mIU, it’s dependent on your urine concentration—the less diluted the urine, the higher the concentration of HCG. Since urine is more concentrated in the morning, a test taken then is more likely to produce a positive result than one taken later in the day. Still, most urine tests will be positive by one to two days after a missed period.

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You should wait to take a pregnancy test until the first day of your missed period. Since HCG is only present once implantation of the egg occurs, there often isn’t enough of the hormone to be detected until you miss your menstrual cycle.

“Pregnancy tests pick up the hormone secreted after implantation, which usually occurs about two weeks after the sperm meets the egg,” says Dr. Culwell. “For women who have regular periods, this usually means that HCG can be detected as soon as you miss a period.”

This, of course, assumes you have a regular menstrual cycle that can be easily tracked and predicted. If this isn’t the case, you may choose to instead track ovulation, or when an egg is released and makes its way to the uterus where it can potentially be fertilized. An at-home ovulation predictor kit can help you track fertilization.

If this method is used, it’s best to take a pregnancy test “approximately 14 days after a documented ovulation,” says Zaher Merhi, M.D., an OB-GYN, reproductive endocrinologist and founder of Rejuvenating Fertility Center with locations in New York and Connecticut.

Signs You Should Take A Pregnancy Test

The biggest indicator it’s time to take a pregnancy test is a missed period. It isn’t the only sign, however. Symptoms that signal it may be time to take a pregnancy test, according to Dr. Merhi, include:

  • Missing a period
  • Breast fullness/soreness
  • Frequent urination
  • Nausea
  • Vomiting
  • Fatigue
  • Abdominal bloating

When Is the Best Time to Take a Pregnancy Test?

You can take a pregnancy test any time of the day. But if there’s a chance you’re early in pregnancy, take it in the morning when your urine is most concentrated so the test can more easily detect the HCG hormone, says Dr. Culwell.

“The best time in the cycle to take a test would be after you have missed a period,” says Dr. Culwell. “This will make it less likely that you might miss an early pregnancy if the HCG levels are too low to be picked up by the test.”

Where To Buy A Pregnancy Test

You can buy a pregnancy test at most drug stores and grocery stores, or even online.

Bestselling Pregnancy Tests on Amazon

How Soon Can You Take a Pregnancy Test?

At-home pregnancy tests are regulated by the Food and Drug Administration (FDA), meaning their accuracy and labeling is evaluated before they reach store shelves. When it comes to the accuracy of at-home pregnancy tests, research shows if the test is used as directed, an inaccurate result is rare. While false-positive pregnancy test results are uncommon, if you do receive an inaccurate result, it’s more likely to be a false-negative. In this case, it’s likely you’re testing too early, before HCG can be detected.

“For most women who have a regular menstrual cycle, a pregnancy test could be taken on the expected day of the period,” says Dr. Merhi. “The earliest [time to test] would be the expected day of the period; however, I usually tell patients to wait at least a few days (or one week) after the expected day of the period in order to lower the chances of having a false result.”

It’s worth noting that at-home pregnancy tests accuracy claims—many of which advertise an accuracy rate of 99% from the day of the expected period—are based on data used in a sterile laboratory testing environment. If you think you received an inaccurate result, you can either wait and test again a few days later or see your doctor for a blood test, which can detect HCG earlier than at-home tests and has an accuracy rate of 99%.

How Accurate Are At-Home Pregnancy Tests?

When used according to the directions, a home pregnancy test can be almost 99% accurate[3]Pregnancy tests. Office on Women's Health. Accessed 7/20/2022. . If you receive a positive result on a home pregnancy test, you should contact your doctor to confirm that you are pregnant and find out what to do next.

When You Should Get a Pregnancy Blood Test

A pregnancy blood test at your doctor’s office is another way to confirm a pregnancy.

“The blood test can detect the pregnancy earlier than an at-home urine test; eight days after ovulation is the earliest a blood test could detect a pregnancy,” says Dr. Merhi.

Should you receive a positive at-home pregnancy test result, your doctor will often perform an in-office blood test to confirm the presence of HCG. This and additional blood tests also provide additional information about your health and the health of your pregnancy.

“Blood tests are also needed to check for complications of pregnancy—for instance, if you are at risk for ectopic pregnancy [pregnancy implanting outside of the uterus], miscarriage or an abnormally progressing pregnancy,” says Dr. Culwell. “[This is] because they can measure whether your pregnancy hormone levels are progressing normally or decreasing.”

Should you experience a miscarriage, HCG can remain in your body for a few weeks, and additional tests taken in the weeks following can lead to a false-positive result, says Dr. Merhi.

How Long Does a Pregnancy Blood Test Take?

A pregnancy blood test can mean a wait of just a few hours or more than a day to receive results. A tube of blood is drawn and sent to a laboratory to obtain a result.

How Accurate Are Pregnancy Blood Tests?

A blood test to detect pregnancy is about 99% accurate as this test can detect smaller amounts of hCG than a urine pregnancy test[4]Pregnancy Testing. Better Health Channel. Accessed 7/20/2022. .

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FAQs

What should I do if my pregnancy test is positive?

If your pregnancy test is positive, call your doctor to find out the next steps.

How soon will a pregnancy test read positive?

A pregnancy test will read positive as early as a few days before you miss your period, but is most accurate if you wait until a day or two after you have missed your period.

Can you be pregnant and still have a period?

It is impossible to get your period while pregnant, but bleeding or spotting can sometimes occur in early pregnancy. Check with your doctor if you experience bleeding or spotting after receiving a positive pregnancy test result.

What can cause a false positive pregnancy test?

You may receive a positive pregnancy test result and then later receive a negative result. This could mean you’re experiencing an early pregnancy loss or an ectopic pregnancy. These are not false positive results. A true false positive is very rare but may be caused by residual hormones after experiencing a miscarriage or having a baby. Some fertility treatment medications containing hCG could give you a false positive result as well.

Can a pregnancy test be negative at night and positive in the morning?

Takeaway. If you do decide to take an at-home pregnancy test at night, it's important to keep in mind that many factors can impact the results. A negative test at night might be followed by a positive test in the morning.

Can I do my pregnancy test in the evening?

Although you may take a pregnancy test at night, the test may be a false negative since urine tends to be more diluted at night. This is why doctors recommend taking a pregnancy test in the morning, especially in the first couple of weeks of pregnancy.

What time is a pregnancy test most accurate?

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.

Is hCG higher in the morning or at night?

HCG is at its highest level in the morning when urine is fresh and not diluted by the liquid you drink during the day. If you test in the afternoon, your urine may not have enough HCG to detect.