What can cause a False Positive Pregnancy Test?

What can cause a False Positive Pregnancy Test – Pregnancy testing can give false positive results, however, this is a very rare situation that happens most often in home-made pharmacy tests, mainly due to errors in using it or being out of time.

Another common cause for this result is the so-called chemical pregnancy, which causes the body to produce the pregnancy hormone even when, in fact, the woman is not pregnant.

In addition, women undergoing treatment for infertility with hCG injections or who have tumors that can produce this hormone may also have a false-positive result in the pregnancy test, either from a pharmacy or from a blood test.

What can cause a False Positive Pregnancy Test

Main causes of false positive

Changes in the result usually happen when the test is out of date and therefore it is very important to confirm the expiration date before using it. However, if it is correct, there are other causes such as:

1. Test did the wrong way

Before using the pharmacy pregnancy test it is important to read the manufacturer’s instructions, especially about the time it is necessary to wait to read the result. This is because some tests may change the result after the recommended reading time.

In addition, before using the test it is also recommended to wash the intimate region with water, as some soaps or intimate creams can react with the test, leading to the appearance of a false positive or negative, for example.

2. Chemical Pregnancy

This kind of pregnancy happens when there is the fertilization of the egg, but the embryo could not get fixed in the uterus. In these cases, the body begins to produce the hormone hCG and therefore can be detected in urine or blood test, however, because the embryo did not remain in the uterus, it is eliminated and a spontaneous abortion with bleeding occurs, which can be confused with delayed menstruation.

3. Use of some medicines

Some medications used in the treatment of infertility problems contain high amounts of hCG, the hormone that is evaluated in pregnancy tests and which therefore can lead to false-positive shortly after treatment.

In addition, other more common medications such as anticonvulsants, diuretics, or tranquilizers may also cause changes in the outcome. That way, it is important to read the package leaflet or have the blood tested at the hospital, informing the doctor about the medicines used.

4. Health problems

Although it is rarer, the false positive can also arise in cases of a disease, especially in cases of hormone-producing tumors, such as in breast or ovarian cancer, for example.


How to avoid false positives

To avoid having a false positive result it is very important to follow all the instructions of the pharmacy test box and, after taking the test, take care of:

  • Repeat the test 3 to 5 days later;
  • Do not re-confirm the test after the specified time;
  • Make an appointment with the gynecologist after 4 to 5 weeks.

However, the most reliable way to avoid outcome changes is to do the blood test with beta hCG evaluation, because in these cases there is less chance of changes in the result. In addition, prior to the exam, the doctor will make an assessment to determine if there are any medications or other situations that may provoke a false positive.