A pregnancy test taken at home can yield false positive results for several reasons. Even a pregnancy test performed on blood can show a false positive under certain circumstances. False positive are rare, but they do occur. Seeing a doctor soon after getting a positive pregnancy test result is always a good idea.

A home pregnancy test works by measuring Human Chorionic Gonadotropin (HCG). When a woman is pregnant, placenta produced to nourish the baby produces HCG in great volume. Normally most variants of the home pregnancy test cannot be considered accurate until taken on the date or a few days after a missed period.

One common corrupting agent to the pregnancy test is exposure to soaps or detergents. These can cause a false positive result. Thus urine collection should be done carefully to avoid such exposure. Many tests simply have one urinate directly on the stick used to give results. If one must urinate into a cup, the cup should be very clean and presumably free of any leftover soap or detergent deposits.

Another frequently common reason for a false positive pregnancy test is when women are using HCG injections in order to assist in getting pregnant. This means that HCG levels may register even when a pregnancy does not exist. Normally a blood test or obstetric examination helps to determine a true pregnancy from a false one. Theoretically, a man being injected with HCG could have a positive pregnancy test, even though one would know the man was not pregnant.

Other medications may also cause a false positive on a pregnancy test. These include anti-convulsants, medications to treat Parkinson’s disease, certain tranquilizers, and certain diuretics. Many of these medications could be dangerous to a growing unborn child, so it is very important to confirm results with an obstetrician if you are taking any of these medications.

Trophoblastic tumors, which grown in a woman’s reproductive system, may also yield a false positive on a pregnancy test. These tumors can also make someone feel pregnant, causing morning sickness and swelling in the abdomen. This is because they also produce HCG. When caught early, these tumors generally can be removed and cause no further problems.

In some cases, hysterical or false pregnancy can also produce HCG that will be detectable on a home pregnancy test. As with trophoblastic tumors, a woman may manifest pregnancy symptoms that make the pregnancy seem more plausible.

In all cases, a positive pregnancy test means seeing a doctor soon to discuss obstetric care and set up a plan for medically addressing the pregnancy. If you have any of the conditions or take any medications above that might corrupt the test, this should be brought to a doctor’s attention so the pregnancy can be verified.