Missed Period But Negative Pregnancy Test? Here's Why That Can Happen

Why Your Period May Be Late + What Can Cause a False Negative Pregnancy Test

woman looking at a negative pregnancy test after a missed period
If you missed your period and you got a negative pregnancy test, you may actually be pregnant... or not.. Sam Edwards / OJO Images / Getty Images

Missed period but negative pregnancy test? There are several reasons this may happen.

It is possible that...

  • You actually are pregnant, but the pregnancy hormones haven't built up enough. 
  • You aren’t pregnant. Your period is late for another reason. (More on this below.)
  • You are pregnant, but the test isn’t working. 
  • You are pregnant, but something is wrong.

This can be an emotionally difficult experience.

The good news is that most of the time, it'll be resolved in a few days.

You'll either get your period, or you'll take another test and discover you are pregnant. 

Other times, it may turn out that something is wrong. But this is a rare situation.

Let’s look at all the possibilities.

Most Common Reasons for a False Negative When You’re Actually Pregnant

A false negative pregnancy test is when the test comes up negative, but you are actually pregnant.

The most common reason for a false negative is that you took the test too early.

Now, I know you’re late for your period. However, you may have ovulated later this month.

Even if you have regular periods, it's normal to occasionally have an off cycle.

You can't get a positive pregnancy test until a certain set number of days has passed since ovulation (which is the time of conception.)

If ovulation came later this month, you will need to test later.

There are many reasons you might ovulate later than you typically do.

 (More on this below when we discuss why you may miss your period even if you aren’t pregnant.)

Another possible reason for a false negative is there isn’t enough hCG in your system.

Pregnancy tests look for the pregnancy hormone hCG. This hormone increases as the pregnancy progresses. The range of normal for each day varies widely.

It’s possible your levels aren’t high enough yet.

An early pregnancy test may pick up very low amounts of hCG. However, it’s possible you don’t have enough circulating hCG to get a positive result even on a sensitive test.

This doesn’t mean anything is wrong. What’s important isn’t how much hCG you have, but how quickly it doubles and increases. (That can only be measured with a blood test.)

Another common reason for getting a false negative is not having enough hCG in your urine.

This may happen if you drank a lot of water, diluting your urine.

This may also happen if you took the test later in the day. The hCG concentration is higher when you’ve held your urine for awhile. (Just like what naturally happens during sleep. This is why it's recommended to take a pregnancy test in the morning.)

Things That Can Go Wrong With the Pregnancy Test Itself

A false negative can also happen due to test error.

If you wait too long to read the results, you may get a false negative.

(However, false positives are more common with reading a test too late.)

Make sure you follow the directions of your particular pregnancy test. Read the result in the time window recommended to avoid confusion.

Another possible cause for a false negative is an expired test.

Storing the test improperly (like in a wet bathroom cabinet) can also cause it to malfunction.

Rare Causes of Pregnancy Test Malfunction

A rare but strange cause for a false negative is being too far along in your pregnancy.

For example, if your period is months late, a pregnancy test may come up negative.

This is called the variant hook effect.

The molecular structure of hCG changes over the pregnancy. At-home pregnancy tests are intended for early pregnancy. They may not react with later forms of hCG.

Another rare but possible reason for a false negative is if you’re expecting triplets or even twins.

This may be caused by what is known as the high dose hook effect.

Ironically, unusually high levels of hCG can cause the test to give a false negative result.

A very rare cause of a false negative is if the hCG hormone in your body doesn’t react with the anti-hCG chemicals in the pregnancy test.

If this is the problem, you may need to wait a few more days before you can get a positive result. Or, you may need to have a blood test.

In all of the above situations, a serum pregnancy test (via blood work) and/or ultrasound may be needed to confirm pregnancy.

Rare and Potentially Worrying Reasons for a False Negative Pregnancy Test

An ectopic pregnancy is when the embryo implants somewhere besides the uterus. An ectopic pregnancy usually occurs in the fallopian tubes, but it can occur elsewhere in the body.

An ectopic pregnancy doesn’t develop the way it should. The placenta formation is delayed, and this delays the production of hCG.

An ectopic pregnancy can be dangerous. If your period is late and you are experiencing severe pain, contact your doctor immediately.

Ectopic pregnancies are rare – occurring in about 1 in 40 pregnancies – but they can be deadly.

Of pregnancy-related deaths, 9% are due to ectopic pregnancy.

Another rare but worrisome cause of false negatives is gestational trophoblastic disease. This is more commonly known as a molar pregnancy.

Gestational trophoblastic disease (GTD) is a rare type of tumor that forms from a developing embryo.

In less than 1 in 100 cases, a healthy baby can form in a molar pregnancy. Usually, GTD ends in miscarriage.

GTD causes extremely high levels of hCG. As mentioned above, high levels of hCG can throw off an at-home pregnancy test and give a negative result.

GTD is a tumor, but it’s rarely cancerous.

Treatment involves having a D&C. If pregnancy hormone levels remain high, chemotherapy may be needed.

Reasons Your Period Is Late That Are NOT Pregnancy Related

The most common reason for a late period and a negative pregnancy test is that your period is simply off this month... and you’re not pregnant.

Having one or two irregular cycles a year is nothing unusual. It can be caused by a number of things, including...

  • illness
  • travel
  • poor sleep
  • unusual stress

If the stress or illness came just before ovulation time, it can throw your entire cycle off. 

If you’re breastfeeding and your cycles have just restarted, you can expect your cycles to be irregular for a while. This can make it difficult to know when your period is really late.

If you’re over 45, and your period is late, you may be entering menopause. But don’t assume you can’t be pregnant. Test anyway!

Did you just stop birth control pills? Remember that birth control controls your cycles. YTou don’t really know what your body’s natural cycle lengths is yet. 

It’s also not uncommon for the first few cycles to be slightly irregular.

You can get pregnant in the very first month after birth control. So, don’t assume you can’t be pregnant. Test anyway.

Missed Period and Negative Pregnancy Test After Fertility Treatment

Another possible cause for an off cycle is fertility treatment.

If your cycles are typically short, fertility drugs like Clomid may extend your cycle length.

If you just went through an IVF, IUI, or injectable cycle, this can also throw off your expected period date.

You likely know when you ovulated if you were monitored during treatment.

You can consider “ovulation day” to be...

Count fourteen days from whatever your “ovulation day” was.

If fourteen days haven’t passed, your period isn’t really late yet.

When to Call Your Doctor

If your period is one to two weeks late, and you still are getting negative pregnancy tests, a visit to your gynecologist for a pregnancy blood test is recommended.

What if your period is always late?

If your periods are frequently irregular, talk to your doctor about when they’d like you to call. Most doctors will want to induce a period if you go more than two or three months without menstruating.

Also, if your cycles used to be regular but become irregular, or your cycles are irregular for more than three months after stopping birth control, you should see your doctor.

Irregular cycles can be a risk factor for infertility. Get checked out.

The sooner you get things evaluated, the sooner you can know what’s going on and receive proper treatment.

If you have additional worrisome symptoms along with a late pregnancy test, don’t wait to call your doctor.

If you have a late period and...

  • severe abdominal or pelvic pain
  • nausea or vomiting
  • fainting or extreme dizziness
  • shoulder pain
  • any of the above in combination with sudden vaginal bleeding

Contact your doctor immediately and/or go to the emergency room! You may have an ectopic pregnancy.

Ectopic pregnancy can lead to loss of your fallopian tubes, your fertility, and even death.

It’s better to get checked out and find out all is fine. Don't ignore worrisome symptoms and risk your life and health.


D Yunus, H Muppala, F Hamer, F Clarke. “Three Consecutive False Negative Pregnancy Tests in a Twin Pregnancy: A Case Report.” The Internet Journal of Gynecology and Obstetrics. 2006 Volume 6 Number 2. http://ispub.com/IJGO/6/2/10533

Gestational Trophoblastic Disease. American Cancer Society. Accessed December 29, 2015. http://www.cancer.org/cancer/gestationaltrophoblasticdisease/detailedguide/gestational-trophoblastic-disease-what-is-g-t-d

Nerenz, Robert D.; Gronowski, Ann M. “Point-of-Care and Over-the-counter Qualitative Human Chorionic Gonadotropin (hCG) Devices Remain Susceptible to False-Negative Results Caused by Excess hCG β Core Fragment.” Published August 28, 2013. doi: 10.1373/clinchem.2013.212795 Clinical Chemistry November 2013 vol. 59 no. 11 1672-1674  http://www.clinchem.org/content/59/11/1672.long

Nerenz, Robert D.; Gronowski, Ann M.; Song, H. “Screening Method to Evaluate Point-of-Care Human Chorionic Gonadotropin (hCG) Devices for Susceptibility to the Hook Effect by hCG β Core Fragment: Evaluation of 11 Devices.” Published January 24, 2014. doi: 10.1373/clinchem.2013.217661 Clinical Chemistry April 2014 vol. 60 no. 4 667-674 http://www.clinchem.org/content/60/4/667.short

Statistics on Ectopic Pregnancy. Florida Hospital. Accessed December 29, 2015. https://www.floridahospital.com/ectopic-pregnancy/statistics

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