Can You Get a False Negative Pregnancy Test?

If you've missed your period, a negative pregnancy test result can be confusing. Whether you're using contraception or actively trying to conceive, you might be wondering, "Is it possible to get a false negative pregnancy test?" As it turns out, the answer is yes.

Home pregnancy tests are very reliable, but false negatives are possible in rare occasions. They might happen when your body hasn't produced enough pregnancy hormone (hCG) for the test to pick up. Other factors—such as user error or an expired test—might also be to blame.

Keep reading to learn more about false negative pregnancy tests, including what causes them and what to do if you're doubting the results.

How Do Home Pregnancy Tests Work?

Urine pregnancy tests detect the hormone known as human chorionic gonadotrophin (hCG), which is produced during pregnancy. To use a home pregnancy test, a person pees on a stick containing a reactive paper that's able to detect whether there's hCG in the urine. Within a few minutes or less, a negative or positive result is shown.

How Accurate Are Pregnancy Tests?

Many home pregnancy tests claim to be 99% accurate. But accuracy depends on a host of factors, including how far along a person is in pregnancy when they take a urine test at home.

“Depending on the brand and specific test type, there are different detection thresholds for the hormone,” explains Alan Copperman, M.D., FACOG, an infertility specialist, managing director and CEO of RMA New York, and medical advisory board member at Progyny. “For example, some results for pregnancy tests read positive when the hCG is greater than 50 miu/mL, and others are more sensitive.” 

Urine pregnancy tests are not as accurate as blood pregnancy tests, which are given in a health care provider's office. These can pick up even a slight level of hCG in a person’s blood. “While blood tests can detect levels as low as 5 mIU/ml, the most sensitive urine tests can only pick up the presence of HCG if it's closer to 20 mIu/ml or more,” explains Janet Choi, M.D., board-certified reproductive endocrinologist and chief medical officer for Progyny.

Pregnancy tests may show a positive result if they are performed two weeks after ovulation. But it’s best to take a home pregnancy test after a missed period.

What Can Cause a False Negative Pregnancy Test?

Some urine pregnancy tests can detect a pregnancy as soon as six days before a missed period, but there can be slight variations. 

"If a pregnancy test is taken too early, the test can look negative when a woman is really very early in her pregnancy. This is called a false negative,” explains Comfort Ughanze, M.D., an OB-GYN and assistant professor at McGovern Medical School at UT Health Houston. “If possible, it's best to wait until after a missed period" before taking a pregnancy test.

Dr. Ughanze explains that other common reasons for a false negative pregnancy test include:

• Taking the test incorrectly
• Using an expired test
• Miscalculating your menstrual cycle
• Testing at the wrong time of day (For most accurate results, take the test first thing in the morning when your urine is most concentrated)

Can You Be Pregnant With a Negative Result?

Yes, it's possible to be pregnant with a negative result. A false negative may simply mean that your pregnancy hasn't progressed far enough for hCG levels to be picked up by the test, says Dr. Cooperman. False negatives might also indicate an error with the test (for example, using an expired test or following directions improperly).

Can Too Much Pee on a Pregnancy Test Make It Negative?

Urinating too much on a urine pregnancy test should not cause a false negative result. But diluted urine, or urine with a higher water content, can impact a pregnancy test by skewing results. “A general tip I like to share with my patients is that the first morning urine is often the best time to test because it is likely the least diluted,” explains Dr. Cooperman.

Can I Be Several Weeks Pregnant and Still Test Negative?

Yes, that can be possible, but it’s rare. The likely cause is variations in a person's menstrual cycle. For example, "some women might think they are five weeks pregnant but are really only four weeks pregnant," says Dr. Ughanze. "If a woman tests too early, the result can be falsely negative."

The bottom line: It's highly recommended to take a pregnancy test at the right moment. That's typically after a missed period and testing with urine first thing in the morning. This will give you better chances of getting an accurate result.

What Can Cause a Missed Period and Negative Result if You’re Not Pregnant?

If your period is late or missed but you're not pregnant, there are a few possible causes. "Missed periods can occur for many different reasons besides pregnancy," confirms Dr. Ughanze. 

Some reasons you may miss a period—but not be pregnant—include:

• Stress
• Changes in weight
• Thyroid disorders or other medical conditions
• Birth control methods (such as birth control pills, vaginal rings, etc.)
• You’ve been traveling
• Illness
• You’re menopausal or perimenopausal
• You're breastfeeding

Dr. Ughanze says if a person is missing their periods and is not pregnant, it's best to be evaluated by a health care provider.

What Should You Do After a Negative Pregnancy Test?

If you've gotten a negative pregnancy test, but you're suspicious about the results, you can repeat the test in two to three days. Or you can head to your health care provider for a quantitative blood test, which measures the exact amount of hCG in your blood.

Always make sure to get support from a loved one or medical professional if you're having a hard time dealing with the results of your pregnancy test.