What Are the Causes of False Negative Pregnancy Tests and How to Avoid Them?

False negative pregnancy tests aren’t very common, but they can still happen. What Are the Causes of False Negative Pregnancy Tests? If you’ve missed your period and received a negative test result, it can be confusing. Whether you’re using birth control or actively trying to conceive, you might be asking yourself, “Is it possible to get a false negative?” The answer is yes.

Home pregnancy tests are usually reliable, but false negatives do occur, especially if your body hasn’t produced enough pregnancy hormone for the test to detect. Other factors, such as a faulty test or specific medical conditions, can also lead to inaccurate results.

Here’s everything you need to know about false negative pregnancy tests, including what can cause them and what steps to take if you’re unsure of the results.

How Do Home Pregnancy Tests Work?

At-home pregnancy tests detect the presence of the hormone human chorionic gonadotropin (hCG), which is only produced during pregnancy. When using a home test, you urinate on a stick that has reactive paper designed to detect the hCG hormone. After a few minutes, the test will display either a positive or negative result.

How Accurate Are Pregnancy Tests?

Most home pregnancy tests claim to be about 99% accurate. However, the accuracy of the test depends on several factors, including how far along you are when you take the test.

“Different brands and types of tests have varying thresholds for detecting hCG,” explains Dr. Alan Copperman, an infertility expert and managing director of RMA New York.

While urine-based tests are quite accurate, blood tests administered by a healthcare provider are even more precise, as they can detect very low levels of hCG. “Blood tests can pick up hCG levels as low as 5 mIU/ml, whereas the most sensitive home urine tests can only detect hCG at 20 mIU/ml or higher,” says Dr. Janet Choi, chief medical officer for Progyny.

First Trimester Tips: What to Expect in the First 13 Weeks of Pregnancy

What Are the Causes of False Negative Pregnancy Tests? Reasons for a False Negative Pregnancy Test Result

Although home pregnancy tests are generally dependable when used correctly, What Are the Causes of False Negative Pregnancy Tests? False negatives are possible, and in fact, they happen slightly more often than false positives. Here are some reasons why you might get a false negative pregnancy test result:

1. You Tested Too Early

“If a pregnancy test is taken too early, it may show negative even if you’re actually pregnant,” explains Dr. Comfort Ughanze, an OB-GYN and assistant professor at McGovern Medical School in Houston.

Every individual has different hCG levels, so if you test too soon, your body might not have produced enough of the hormone to be detected. This is particularly true for people with irregular menstrual cycles, as pinpointing ovulation can be tricky.

Tip: To increase the accuracy of your test, wait until after you’ve missed your period or ask your healthcare provider for a blood test.

2. You Tested Too Late

In rare cases, a pregnancy test might show a negative result because you’re too far along in your pregnancy. Known as the “hook effect,” this happens when hCG levels are so high that they overwhelm the test, causing it to display a false negative.

3. You Read the Results Too Early

If you check the test too soon, there might not be enough hCG in your urine to cause a color change on the test strip, resulting in a false negative. Following the test instructions carefully and waiting the full time recommended is key.

4. The Test Was Expired or Faulty

Using a pregnancy test past its expiration date can lead to unreliable results, warns the FDA. Expired tests can lose sensitivity to hCG, leading to false negatives.

Tip: Take the test first thing in the morning when your urine is most concentrated with hCG. If you’re very hydrated, the hormone might be diluted, which could result in a false negative.

5. You’re Pregnant with Multiples

In some cases, if you’re expecting twins or triplets, a false negative result may occur due to the hook effect. Higher levels of hCG can interfere with the test’s ability to provide an accurate result.

6. You Have a Molar Pregnancy

An unusual condition called a molar pregnancy can also cause a false negative. In a molar pregnancy, abnormal tissue grows inside the uterus instead of a fetus. This condition produces extremely high levels of hCG, which can disrupt urine-based pregnancy tests.

7. You Have an Ectopic Pregnancy

An ectopic pregnancy, where the embryo implants outside of the uterus (such as in a fallopian tube), can also lead to a false negative. In these cases, hCG levels may rise more slowly, which can prevent early detection through a home pregnancy test.

When to Seek Medical Attention

If your period is late and you’re experiencing significant pain, it’s important to seek medical care immediately. While rare, ectopic pregnancies can be life-threatening if left untreated. Around 9% of pregnancy-related deaths are caused by ectopic pregnancies, so early intervention is crucial.

What to Do After a Negative Pregnancy Test

If you receive a negative test result but still believe you’re pregnant, you can retest in a few days or consult your healthcare provider for a blood test, which is more sensitive.

It’s also important to reach out to someone for support if you’re feeling anxious or upset about the test results. Whether it’s a friend, family member, or healthcare professional, having emotional support can help you process your feelings.

Reasons for a Late Period Other Than Pregnancy

If your period is one or two weeks late and you’re still testing negative for pregnancy, it’s a good idea to visit your healthcare provider to rule out any complications. One of the most common reasons for a late period and a negative pregnancy test is that your cycle may simply be delayed.

Having an irregular cycle once or twice a year is relatively normal and doesn’t necessarily indicate a health issue. “There are several factors beyond pregnancy that can cause a missed period,” explains Dr. Ughanze.

Some non-pregnancy reasons for a missed period include:

Stress
Poor sleep patterns
Intense exercise
Changes in weight
Hormonal birth control
Travel
Illness
Perimenopause or menopause
Breastfeeding

If your periods are frequently irregular, consult with a healthcare provider. Conditions like polycystic ovary syndrome (PCOS) or thyroid disorders can cause irregular ovulation, and addressing these issues can help prevent future complications, including infertility.

Final Thoughts

While false negative pregnancy tests are rare, they do happen. If you’re in doubt, retesting or seeking a blood test from your healthcare provider can give you peace of mind. It’s always a good idea to consult a doctor if your periods are irregular or if you’re experiencing symptoms of pregnancy despite negative test results.

Read More: 5 Ways to getting ready for baby arrival

When Does the First Trimester End? A Complete Guide to Early Pregnancy