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What are Some Alternative Causes of a Positive Pregnancy Test?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Sometimes a positive pregnancy test doesn’t mean a woman is or will remain pregnant. There are numerous things that may cause what are known as false positives or simply inaccurate readings. On the other hand, it should be stated that even home pregnancy tests have about a 97% accuracy rating if directions are strictly followed, and things like blood tests at a lab or doctor’s office are considered more precise.

Most pregnancy tests screen for hormones like human chorionic gonadotropin (HCG) that are usually only present when pregnancy is occurring. Actually, it isn’t completely accurate to say that HCG can’t occur at other times. Hormone treatments meant to increase fertility may have high levels of HCG in them, and the body produces HCG at other times. Certain types of tumors growing in the uterus or ovaries can cause high HCG levels and an inaccurate, positive pregnancy test. There have been instances where psychosomatic illnesses like hysterical pregnancy have boosted these hormones, and this can fool a pregnancy test easily.

Female reproductive system.
Female reproductive system.

Since the female body can produce this hormone at any time, it is conceivable for it to do so at times other than pregnancy. Having a sudden upsurge in HCG levels may also cause symptoms similar to early pregnancy like morning sickness. Unfortunately, these symptoms combined with a positive test can be extremely misleading, and be very frustrating to experience when are not truly an indication of pregnancy.

Home pregnancy test showing positive and negative results.
Home pregnancy test showing positive and negative results.

There are other ways to get a positive pregnancy test. Early testing can lead to detection of an extremely early pregnancy that ends in miscarriage, usually before the time that a period could even be missed. This is called a chemical pregnancy. It’s almost the fault of more accurate, early testing that women would even notice a positive result that would be followed by a negative result later. Before it was common to test prior to a missed period, few women were even aware of these short pregnancies.

An ultrasound confirms pregnancy.
An ultrasound confirms pregnancy.

Sometimes the presence of other chemicals can disrupt tests. A collection cup might be contaminated by soaps or detergents inside that create a positive pregnancy test. Alternately, some prescribed medications like anti-seizure drugs, water retention medicines, or medications for some degenerative neurological conditions interfere with testing.

Bad testing protocol may also result in a positive pregnancy test. One of the most common causes of a home test reading falsely positive is waiting longer than the time stated to read the test. Usually, results are only good for a few minutes. Tests can also streak and make a mark that looks like a positive result, but isn’t.

A blood test is used to measure a woman's production of the HCG hormone during pregnancy.
A blood test is used to measure a woman's production of the HCG hormone during pregnancy.

Ultrasound is one way to confirm an actual pregnancy. In the event of a positive test that seems doubtful, this is one means for verifying or ruling out results. Sonograms can usually be performed four to six weeks after conception and confirm presence, or not, of a fetus.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments

Comparables

@ Babalaas- Thanks for the info, but an early positive pregnancy test was not the case. She took the test a week after she was late, and the doctor confirmed about a week or ten days after that.

Babalaas

@ Comparables- You ask an interesting question. The article stated that a pregnancy test tests for hormone levels, and I know that fluctuations in hormone levels can be a cause for miscarriage. As for predicting a miscarriage with a positive pregnancy test, the article said that a test taken too soon can show a chemical pregnancy. Maybe this was the case.

Comparables

Does anyone know if a faint positive pregnancy test can be an indicator of an impending miscarriage? My wife had a miscarriage and all of the pregnancy tests she took were faint at home and at the doctor’s office. Her first pregnancy was healthy and ended well, but the pictures she has of her test show a dark line. This last one ended in miscarriage at the twelfth or thirteenth week, and it really had her messed up. I am just curious to know if the faintness of the line on the test can speak to anything about a miscarriage.

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    • Female reproductive system.
      By: chart
      Female reproductive system.
    • Home pregnancy test showing positive and negative results.
      By: Tein
      Home pregnancy test showing positive and negative results.
    • An ultrasound confirms pregnancy.
      By: Andrey Chmelyov
      An ultrasound confirms pregnancy.
    • A blood test is used to measure a woman's production of the HCG hormone during pregnancy.
      By: frog-travel
      A blood test is used to measure a woman's production of the HCG hormone during pregnancy.
    • The results of a pregnancy test are usually only good for a few minutes, so they should be viewed right away.
      By: Monkey Business
      The results of a pregnancy test are usually only good for a few minutes, so they should be viewed right away.
    • The presence of other chemicals can disrupt a pregnancy test.
      By: michaeljung
      The presence of other chemicals can disrupt a pregnancy test.