15 Reasons Why A Pregnancy Test Can Give A False Positive And Ways To Prevent This From Occurring

Date November 30, 2017

Home pregnancy tests, which can be obtained from practically any pharmacy, are pretty reliable. In fact, most of them can detect pregnancy with an accuracy of 97%, even from the day after one's menstrual period. The tests work by indicating if the pregnancy hormone (human chorionic gonadotropin) is present in the urine.

But, as with anything else, certain medical or environmental conditions can alter the result and lead to a "false positive." The most common are:

1. Ovary diseases such as PCOD or PCOS

Polycystic ovarian syndrome consists of the development of cysts on the ovaries. These cysts are groups of featureless tissues which affect the functioning of the ovaries. Ovarian cysts can produce hCG even without pregnancy. The hormone is detected in the urine and can give a false positive reading on a pregnancy test.

2. Medication

Hormone supplements, such as hCG injections, can lead to a false positive pregnancy test. Anti-inflammatory medications make urine a certain color which gives the pregnancy test a false positive reading. There is a similar case with Rifampin, which is used to treat tuberculosis, and some medications used to treat Parkinson's disease. Sulfasalazine and pyridium can also lead to a false positive. Other medications can spike the body's production of hCG: anti-depressants and anti-histamines, recreational drugs and narcotics, as well as diuretics.

3. Chemical pregnancies

A chemical pregnancy is a condition which occurs when a pregnancy is unsustainable, as is the case with ectopic pregnancies (when the embryo is implanted somewhere other than the uterus). In such cases, the body produces hCG, but the pregnancy spontaneously terminates. Around 25% of involuntary abortions go undetected, being confused with a heavy menstrual flow.

4. Food

Artificial or natural colors present in foods can lead to a false positive pregnancy test. If you eat turmeric or beetroot, strawberry or rhubarb, you could provoke a false positive pregnancy test. Drink plenty of water and urinate at least three times before taking a pregnancy test to avoid a false positive. These evaporation lines will show a pinkish color. Again, it'll show as a positive result.

5. Incorrect usage of the test

Reading the result after a longer period of time than indicated, using an expired kit, and other incorrect uses can give a false positive reading.

6. Urinary tract infections

Excretory system illnesses such as kidney stones or urinary tract infections can cause urine to become discolored. When ketone bodies begin to appear in the urine of a diabetic patient, the urine turns to a black color. All of these cases can result in a false positive.

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7. IVF or other infertility treatment

Throughout the infertility treatment, doctors administer ovulating hormones to the woman which cause superovulation. This is to guarantee that at least one of them will survive. During IUI, the multiple hormone injections elevate hCG levels. This hCG takes approximately 12 days to disappear from the system. Taking a home pregnancy test after the IUI can cause a false positive pregnancy test result.

8. Expired pregnancy tests

Expired pregnancy tests have degraded the hCG antibodies which are incapable of detecting the hCG hormone in urine. Hence, this could result in a false positive reading.

9. A recently terminated pregnancy

Recently terminated pregnancies don't flow through the system as quickly as quickly as miscarriages. Sometimes, the dead fetus remains for several days. In this case, if the placenta is functioning, it will keep producing positive readings, i.e., false positives.

10. The appearance of evaporation or bleeding lines

Evaporation and bleeding lines are unwelcome. They corrupt the result of the pregnancy test only to leave taking another test as the only other option. Evaporation lines can be colored if your urine is colored or even if it has a reaction to the surrounding air. Bleeding lines are antibodies which display false positives, especially if they get wet.

11. Bleeding by implantation

If you perform the pregnancy test at the moment of implantation, it's possible that the urine has some blood clots. The line which shows a pinkish color after this will return a false positive.

12. Taking the pregnancy test at the wrong time

If the test is done too soon, in general, it's likely to give a false negative, but could also return a false positive. Your period could be right around the corner and the hCG level hasn't risen, in which case the test could read positive because you took a morning-after pill. In this case, you'll receive a positive reading, only for your period to arrive later.

13. Spontaneous abortion

After a spontaneous abortion, hCG levels take time to disappear from the blood. Miscarriages will always return a false positive reading. This is why some women never even know if they have experienced a spontaneous abortion.

14. Leaving the pregnancy test for too long

Leaving the pregnancy test for a long time allows it to react to the atmosphere and give a false positive reading.

READ ALSO: 10 Basic Differences Between First And Second Pregnancies

15. Birth control pills or IUDs (such as Mirena)

Birth control pills alter hormones and can accidentally trigger hCG levels to rise as a result of hormone production. On the other hand, it's possible that this doesn't happen, but for pregnancy symptoms to appear. The mishap with the Mirena is the syndrome after extracting the IUD. There is a remote possibility that this can cause a false positive reading.

How to prevent a false positive pregnancy reading:

  1. Perform the test correctly.
  2. Perform the test only after observing pregnancy symptoms.
  3. Avoid eating foods which contain artificial or natural coloring.
  4. Read the test result within the indicated time on the packet.
  5. Consult your doctor about the results.

Illnesses or medical conditions which can cause a false positive reading:

1. Infertility

Women who undergo fertility treatment, especially to stimulate ovulation, may be taking medicine such as Pregnyl and Humegon. These medications include a form of hCG which can remain in the body for days after the treatment. Women who are prescribed these treatments must follow their doctor's advice in order to not perform the test too soon, thus avoiding a potential false positive reading.

    2. Choriocarcinoma

    Choriocarcinoma is a type of cancer which occurs inside of the womb. The cancerous cells produce hCG which is detected as a pregnancy. Symptoms of choriocarcinoma include vaginal bleeding, pain, and ovarian cysts. Treatment consists of chemotherapy, followed by an observation period of 3 years to detect any possible recurrence.

    3. Pituitary disease

    Conditions affecting the pituitary gland can cause a false positive pregnancy test reading. Pituitary tumors can stimulate the cells in the pituitary gland to produce hCG. Menopause can also affect the pituitary gland, leading to hCG production and false positive pregnancy readings. On rare occasions, the pituitary gland can create hCG even when no condition or tumor is present.

    4. Ovarian cysts

    Corpus luteum cysts in the ovaries can cause false positive readings in pregnancy tests. The corpus luteum remains in the ovary after releasing the egg. Over time, it disintegrates and the cycle repeats. If the corpus luteum fills with blood or fluid it becomes a cyst and remains inside the ovary. The corpus luteum produces hCG, thereby resulting in an inaccurate pregnancy test reading.

    5. Cancer

    Some types of cancer, affecting the bladder and ovaries can cause a false positive pregnancy reading. These cancers can create small amounts of hCG which may be detected by highly sensitive home pregnancy tests.

    As you can see, there are many reasons why a pregnancy test may result in a false positive reading. So, it's a matter of taking these factors into account and consulting your doctor to determine if you really are pregnant.

    Source: The Sun

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    This article is purely for informational purposes. Do not self-medicate, and in all cases consult a certified healthcare professional before using any information presented in the article. The editorial board does not guarantee any results and does not bear any responsibility for harm that may result from using the information stated in the article.