chances of a false positive pregnancy test?

What Are the Chances of a False Positive Pregnancy Test?


If you | ve been trying to get pregnant, seeing two lines (or a plus sign) on a pregnancy test is one of the most exciting experiences. Still, your knee-jerk reaction might be to ask yourself: Is it too good to be true? Rest assured that the vast majority of the time, if you | re getting a positive pregnancy test result, you are, in fact, pregnant! But every once in a while, a false positive pregnancy test can occur. It can be crushing to find out that you | re not actually expecting, and it may leave you with lots of questions and concerns. So what causes a false positive pregnancy test? Moreover, what are the chances of a false pregnancy test? Here, we | ll share how and why this may happen.

In this article:
What is a false positive pregnancy test?
How common are false positive pregnancy tests?
What causes a false positive pregnancy test?
Next steps: How to confirm a positive pregnancy test

What Is a False Positive Pregnancy Test?

Can you get a false positive pregnancy test? Yes, it | s possible in some cases, says Erin DuMontier, MD, an ob-gyn with BJC Medical Group and Missouri Medical Center. So what is a false positive pregnancy test, exactly? Well, it | s pretty much much what it sounds like: Your test result indicates that you | re pregnant when you | re in fact not.

How Common Are False Positive Pregnancy Tests?

Seeing a positive result and later learning you were never actually pregnant can be devastating. The good news for prospective testers is that the chances of a false positive pregnancy test are very low. So just how common are false positive pregnancy tests then? “False positive pregnancy tests are rare and occur less than 1 percent of the time,” confirms DuMontier. Generally speaking, there will be a contributing factor if you | re seeing a false positive pregnancy test. If not, you can assume the test you | ve used is faulty in some way.
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What Causes a False Positive Pregnancy Test?

While a false positive pregnancy test is rather uncommon, there are a few things that can cause this to occur. Essentially, anything that introduces the presence of detectable amounts of the pregnancy hormone human chorionic gonadotropin (hCG) into your body—other than pregnancy, of course—can lead to a false positive result. Keep reading for possible causes.
Recent miscarriage or abortion

If you get a positive result that you weren | t expecting, but you | ve recently had a miscarriage or abortion, you may simply have some pregnancy hormone lingering in your body. “hCG levels can remain elevated for up to four to six weeks after an abortion or miscarriage,” says DuMontier. In this case, you may want to wait another week to test again to ensure your levels are back to what they were before pregnancy (women have a very small, undetectable amount of hCG in their systems even when they | re not expecting). If you still see a positive result after that timeframe, it | s important to follow up with your doctor.
Chemical pregnancy

A chemical pregnancy is another potential factor. Since tests like First Response are so sensitive that they detect a pregnancy six days before the first day of the missed period, more and more early pregnancies are detected now, says Mary Jane Minkin, MD, an ob-gyn and clinical professor at Yale University. “Then, if that early pregnancy stops developing and the woman actually has a very early miscarriage, some women will think of that as a false positive.” Minkin elaborates that this isn | t actually considered a false positive result, though; in this instance, the woman was indeed pregnant at the time of testing. This is one reason why an early pregnancy test can be considered a double-edged sword. Despite the fact that a chemical pregnancy won | t progress, it can still take a while for hCG levels to go down.