Can Twins Cause False Negative Pregnancy Tests?

Can twins cause false negative pregnancy tests?

Yes, there’s a possibility for twin pregnancies meddling with your pregnancy test result. Multiple factors can be at play, including the hCG level of your blood going high or considerably low.

In this article, we have discussed if a twin pregnancy can cause a false negative pregnancy test. So, continue to read if you want to know more.

Understanding Pregnancy Tests

Can twins cause false negative pregnancy tests? Before we get to the answer, it’s essential to know how pregnancy tests and what causes the pregnancy tests to turn out untrue.

hCG is one of the main factors affecting the accuracy of pregnancy test results.

However, there are other factors to consider. For example, the efficiency of the home pregnancy test kit, improper use, test efficiency, and so on.   The reasons for an inaccurate pregnancy test can occur due to different reasons. And no two false pregnancy test results occur due to the same reason.

So, it’s important to first understand how pregnancy tests work.

Here’s How Pregnancy Tests Work

Home pregnancy test kits work by detecting the hormone called hCG (human chorionic gonadotropin). It’s a hormone detection kit that identifies the presence of human chorionic gonadotropin in the blood or urine of a person taking the test. So, how soon will a pregnancy test read positive? Usually, after 12 weeks of conception, hCG increases rapidly in the human body.

So, What’s Human Chorionic Gonadotropin?

It’s a hormone that the placenta produces shortly after a fertilized egg attaches to the uterine lining. The test works by detecting the presence of this hormone in the blood or urine.

The home pregnancy test kits can detect this hormone even when the level of the same can be as low as 25 mIU/mL. 

If hCG is present in the urine of women who conceived recently, the hormone will start a chemical reaction, giving signals about a positive pregnancy.

False Negative Pregnancy Alert! What’s Getting in the Way?

Testing too Early: Yes, the tool can test hCG levels that are as low as 25 mIU/mL in the urine. But, taking the test too early can cause pregnancy tests to come out negative. It’s best to take the test when the hCG level is slightly higher.

Urine Concentration: Testing too late in the day can also cause the test to come out false or negative in this case.  The urine gets diluted later in the day, so the test can return negative.

Test Sensitivity: all the tests are not created the same way and have the same efficiency. Some of the tests have higher sensitivity than the others. So, there’s a chance for the test to come out negative.

Improper use: if you can’t properly use the test kit, then the pregnancy test might come out false. It’s critical to follow all the steps mentioned in the manual by the kit manufacturer.

Expired Tests: It’s critical to check the expiry date of the tests before using them. An expired test can give a negative or false pregnancy result.

Understanding Twin Pregnancies

A twin pregnancy can cause a false negative pregnancy test. If a twin pregnancy is causing the false test, then it’s essential to know how the twin pregnancy works.

Twinning & How It Happens

A twin pregnancy is the result of a woman conceiving two embryos during fertilization. A twin pregnancy can occur due to two different processes – Identical and fraternal twin pregnancy.

Identical Twin Pregnancy

During the early development of the zygotes, the fertilized egg (fertilized by the same sperm) splits into two different embryos and develops into twin pregnancies.

Fraternal Twin pregnancy

On the other hand, fraternal twin pregnancy occurs when a woman releases two different eggs, and both are fertilized by two different sperm cells.

Can Twins Cause False Negative Pregnancy Test?

Yes, there’s a possibility for twins causing false negative pregnancy tests. At the same time, the reasons can be due to all the other factors described above. However, twin pregnancy relates to a high level of hCG, and it can potentially cause a false negative pregnancy test.

Here’s how –

• High hCG levels: if you are testing with multiple pregnancies (like twins or triplets), it can cause the hCG level to go high. Elevated levels of hCG meddle with the home pregnancy tests. It happens when the hCG level is higher than the antibodies present in the test kit. This is also called the ‘hook effect.’
• Timing of the test: The timing of a pregnancy test is elemental to the test being correct or incorrect. Testing too early or too late can affect the accuracy of the test.

How do Twins Cause False Pregnancy Tests?

Women with twin pregnancies tend to have variations in their hCG levels. This can happen to women who are having twins. This can cause the hCG level to reach lower than the minimum threshold needed for an accurate pregnancy test.

Normally, this shouldn’t be the case for most women. However, women undergoing fertility treatment or those who had twin pregnancies at some point should look out for false pregnancy tests due to variations in hCG levels.

So, this can cause difficulty in understanding and interpreting a pregnancy test. It’s best to consult with a healthcare provider who can help you get the right pregnancy test reading.

hCG Levels in Singleton vs. Twin Pregnancies

It’s easier to detect a singleton pregnancy with an hCG test. In this type of pregnancy, the hCG levels rise up to double the amount approximately within 48 hours.

It can reach up to 500,000 mIU/mL, which is much higher than the maximum limit of 250,000 mIU/mL during a singleton pregnancy.  The test can come out false in two ways when it’s a twin pregnancy.

First, the test might get overwhelmed by excessive levels of hCG in the urine or the blood.

Second, the amount of hCG can be lower than the threshold limit of the test. The test must have a proper ability to bind and result in a false negative reading.

Other Reasons for a Negative Pregnancy Test

So, if a twin pregnancy isn’t causing the negative test result, what is? Here are some reasons to stay aware of –

• Do you have an undiagnosed medical condition like PCOS?
• Extreme levels of stress can also cause this test to fail.
• Weight gain or loss can also cause pregnancy tests to come out false negative.
• Stopping hormonal birth control.
• Endometriosis.
• Pelvic inflammatory disease.
• Thyroid conditions.

Signs of Twin Pregnancy Beyond the Test

You can track additional signs of conceiving twins when the pregnancy test comes back false negative. Here’s what you can do –

Higher Levels of Pregnancy Symptoms: you’ll experience other intense pregnancy symptoms like intense nausea, fatigue, and breast tenderness. In addition, the hormone level in the body can also go up.

Rapid Weight Gain: when you have more than one baby, there’s a chance of rapid and high weight gain.

Abdominal Size: A typical gestation will cause the abdominal size to grow. But a twin pregnancy can increase the abdominal size beyond that, and it can grow bigger compared to a singleton pregnancy.

Family History: Women with a family history of undergoing fertility treatment or having twin pregnancies may experience a twin pregnancy. If you are seeing all the other signs of a twin pregnancy along with a family history of giving birth to twins, then there’s a possibility you are carrying twins as well.

Confirm Pregnancy Beyond Home Tests

If your home pregnancy test came out false, and you are seeing pregnancy symptoms, it’s best to check with your healthcare provider.

Here’s what you can do –

Blood Tests

Home urine tests are effective. But, if you are in doubt, it’s better to go for more advanced tests like a blood hCG test. This test helps measure the exact amount of hCG in a woman’s blood. An accurate hCG test using a woman’s blood can also help identify pregnancy results.

Ultrasound Pregnancy Test

There’s nothing better than a visual confirmation of a pregnancy. Through the ultrasound confirmation method, your healthcare provider can help confirm whether you are pregnant, or it was a false pregnancy. Sound waves can help identify twin embryos inside your womb. So, it’s an efficient method for identifying twin pregnancies.

Conclusion

Twin pregnancies have different challenges. Sometimes, it’s not easy to detect them through a home test. So, can twins cause false negative blood pregnancy tests?

Yes, twin pregnancies can cause the hCG level to vary. The varying levels of hCG may be the reason for a negative false test. If you are suspicious of the home pregnancy going wrong, it would help to take a hCG blood test through your healthcare provider.

NB: the information provided in this article is purely based on several research we have found on the internet. It clarifies the possible reasons for a false negative pregnancy test. However, it’s best to always check with your healthcare provider for an accurate result. Thank you for reading.

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