Reasons for False Positive Pregnancy Tests
Pregnancy tests, when used correctly, are almost always accurate. As long as you wait long enough to use one and as long as the test isn’t expired, you can usually trust the result. If you’re going to have an unreliable result, it will almost always be a false negative, where the test just isn’t measuring your hCG levels accurately. However, it is possible to have false positive pregnancy tests, as well.
Here are some of the possible causes of a false positive pregnancy test:
- You’ve had a miscarriage or a pregnancy ended in the previous eight weeks. It can take that long for the hCG levels in your system to drop.
- You are taking a fertility drug that contains hCG. These aren’t particularly common, but they are occasionally used.
- You’re using an expired pregnancy test. Usually, a pregnancy test that’s passed its expiration will just not be able to register the hCG, and you’d have a false negative. However, depending on whether or not the test has been exposed to heat or moisture, there is a chance you might get a false positive pregnancy test.
- You have certain medical conditions. There are some medical conditions that can cause your body to produce hCG even when you’re not pregnant.
- You’ve had a chemical pregnancy. This happens when a fertilized egg implants in your uterus and your body produces hCG, but then the fertilized egg stops developing because of an abnormality or some other reason. The fertilized egg never becomes an embryo, but you may have enough hCG to test positive. It’s estimated that around a third of fertilized eggs may experience this.
- You have an ectopic pregnancy. This means that the fertilized egg implants somewhere other than the uterus. There is no way to move the fertilized egg into the uterus, and it will not correctly develop. An ectopic pregnancy can result in a false positive pregnancy test, although it does not always do so.