Can You Be Pregnant and Still Get a Negative Pregnancy Test?

It Is Possible, But There Are a Few Key Ways to Prevent It

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Question:

Can You Be Pregnant and Still Get a Negative Pregnancy Test?

Answer:

Modern home pregnancy tests (the kinds that encourage you to urinate on a stick to look for the presence of human chorionic gonadotropin or hCG, a hormone that's produced during pregnancy) are fairly reliable. So most of the time, getting a negative result on a pregnancy test means that you are probably not pregnant. But there are a few situations in which a pregnant woman could, theoretically, get what's called a "false negative" on a pregnancy test.

  • Testing too early: Pregnancy tests will always be more accurate if you wait until your period is late before testing. Even a test marketed as giving an early answer can give you a false negative if you test before your menstrual period is due. For example, say that you tend to have a typical, 28-day menstrual cycle. You're more likely to get an accurate reading from a pregnancy test if you wait until you haven't had a period for at least 29 days. To be extra safe, you might even consider waiting (if you can stand it!) until day 36, since menstrual cycles in adult women can be anywhere from 21 to 35 days long. (Menstrual cycles in young teens can even be as long as 45 days.) When you become pregnant, your level of hCG tends to double every two to three days in the early weeks of gestation, and if you test for pregnancy too early, your level of hCG may be so low that it's undetectable by an at-home pregnancy test. 
  • Not conducting the test properly: If you make a mistake while using the test, such as not using enough urine on the test stick or not waiting long enough to see a result, you may get an incorrect result. But usually if the control line shows up, your test result should be accurate.

  • Testing late in the day: In early pregnancy, it is possible that drinking a lot of water during the day and testing in the afternoon or evening could affect the accuracy of the test. When urine is diluted, it's harder for an at-home pregnancy test to determine whether hCG is present. That's why most pregnancy test manufacturers recommend testing first thing in the morning. But this should be a factor only in the first few days after your missed menstrual period; after that, usually even a test later in the day should give a positive result.

    If you get a negative pregnancy test after having previously had a positive pregnancy test, you may be having a miscarriage—especially if you are also having abdominal cramping and vaginal bleeding and if you notice the loss of any pregnancy symptoms (such as fatigue, nausea, and sore breasts). But there is a slim chance that one of the issues in the bullets above might be affecting the accuracy of your second pregnancy test if you are still in very early pregnancy. When in doubt, call your doctor's office for advice.

    If your period is late but your pregnancy test is negative, there are a number of possible explanations for why your period might be late. Call your doctor for a blood test if you believe that you are pregnant.

    Source:

    US Dept of Health and Human Services, "Pregnancy Tests: Frequently Asked Questions." National Women's Health Information Center Apr 2006. Accessed 17 Nov 2008.

    http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html

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