Can You Rely on a Negative Pregnancy Test?

A woman getting negative pregnancy test
A woman getting negative pregnancy test

When it comes to pregnancy tests, false negatives can happen. A negative pregnancy test may not always indicate that you are not pregnant. There are various reasons why this can occur. In this article, we will explore the reliability of negative pregnancy test and what factors can cause false-negative results.

Related: What Is the Toothpaste Pregnancy Test?

What are Reasons for a Late Period?

A delayed period does not necessarily indicate a problem, especially if you are not trying to conceive. However, what does it mean if your period is late, and you’re not pregnant? Although there is no one-size-fits-all answer, many reasons could explain why your period is absent. We will discuss eight common reasons why your period may be late, what they mean, and how to manage them.

Irregular cycles are common during the early stages of puberty. It is usual for adolescents to have irregular cycles for the first three years after they start their periods. This is because the ovaries may not be releasing an egg every month yet, since hormone levels are still changing.

However, if you are past that phase, there are many other reasons why you might have an irregular period.


Stress is one of the most common reasons for a late period. There are many types of stress, including:

  • Emotional stress caused by relationship problems, depression, or anxiety
  • Physical stress caused by surgery, injury, or illness such as viral or bacterial infections, diabetes, or inflammatory diseases of the gastrointestinal tract.

Some stress is normal, but too much of it can disrupt the body’s hormonal balance, leading to a late or missed period.

The menstrual cycle is regulated by a complex system that includes brain structures (the hypothalamus and pituitary glands), the thyroid gland, the ovaries, and the uterus. Stress can interfere with the body’s cycle regulation by affecting the hypothalamus. When it does, the body can focus only on vital processes and postpone the next period until the situation improves.

Once the stress level is reduced, menstruation is restored in most cases. However, if this does not happen, it may be necessary to consult a healthcare provider. Proper stress management, such as meditation and exercise, can be helpful.

Weight Loss

Weight fluctuation is another common reason for a late or missed period. Being underweight can also prevent a person from getting their period. Rapid weight loss due to dieting or excessive exercise can also affect the body’s hormones. The body needs time to recover after losing weight in a short amount of time. Staying healthy and maintaining an active lifestyle can help menstrual cycles become regular again.

Excess Weight

Excess weight can also affect ovulation by altering the body’s levels of estrogen and progesterone. This can cause irregular periods.

Birth Control

Starting or stopping hormonal birth control can cause changes to the menstrual cycle. Birth control pills contain the hormones estrogen and progestin, which prevent the ovaries from releasing eggs and significantly reduce the odds of becoming pregnant. They can also reduce the frequency of periods. For some people, it may take up to three months before their cycle goes back to normal after they stop using hormonal birth control.

Polycystic Ovary Syndrome (PCOS)

PCOS is a common condition that causes irregular periods. This condition causes the body to produce a higher amount of androgen. It also causes small cysts to form on the ovaries when follicles don’t rupture to release eggs. Common symptoms of PCOS include:

  • Excess facial hair growth (hirsutism)
  • Infertility
  • Weight gain
  • Acne and oily skin
  • Male pattern baldness

If any of these symptoms are present in addition to late or irregular periods, a healthcare provider can perform tests to diagnose PCOS and recommend treatment.


Pregnancy is another common cause of late periods. If a period is more than a week late, following unprotected sex anytime since the last period started, there’s a chance of pregnancy. Home pregnancy tests can typically determine pregnancy starting on the first day of a late period. Blood tests detect human chorionic gonadotropin (hCG) in the blood and can be done before the period is late. This test is performed by a health care provider.

Thyroid Problems

The thyroid gland plays a significant role in regulating the body’s metabolism and hormonal balance. It is crucial to control thyroid during pregnancy for the well-being of both the mother and the developing baby. An underactive thyroid gland (hypothyroidism) can cause irregular or missed periods. This is because the thyroid gland produces hormones that regulate the menstrual cycle. Other symptoms of hypothyroidism include fatigue, weight gain, constipation, and depression. If hypothyroidism is suspected, a health care provider can perform a blood test to measure thyroid hormone levels and recommend appropriate treatment.

Perimenopause and Menopause

Perimenopause is the transition period before menopause when hormone levels begin to fluctuate, and periods become irregular. Menopause occurs when the ovaries stop releasing eggs, and menstrual periods stop completely. The average age for menopause in the United States is 51 years old, but it can occur earlier or later for some individuals. Some common symptoms of perimenopause and menopause include hot flashes, night sweats, mood swings, vaginal dryness, and trouble sleeping.

How Home Urine Pregnancy Tests Work?

Urine pregnancy tests work by detecting the presence of a hormone called human chorionic gonadotropin (hCG) in a woman’s urine. This hormone is produced by the placenta after a fertilized egg implants in the uterus.

The test strip contains antibodies that are designed to react with hCG molecules. When a woman urinates on the test strip, the hCG in her urine binds to these antibodies, causing a reaction that produces a visible line or symbol on the test strip.

Most urine pregnancy tests are highly accurate when used correctly, and can detect hCG levels in a woman’s urine as early as one week after a missed period. However, it’s important to follow the manufacturer’s instructions carefully and to use the test at the appropriate time in order to get an accurate result.

Are Home Pregnancy Tests Reliable?

In the past, the only way for women to know if they were pregnant was to see a doctor. Later at-home pregnancy tests were invented.

Since then, the technology used in these tests has greatly improved. When used correctly, they’re almost 99% accurate. But it’s important to read the directions carefully and follow them closely. Any missed steps or timing issues can give you the wrong results.

The test strip is designed to track the levels of a hormone called human chorionic gonadotropin (hCG) in your urine. HCG is produced in your body once a fertilized egg implants in the uterus. Your body only produces this hormone if you’re pregnant (except in the rare case of some cancerous tumors). HCG levels double roughly every 48 hours, but this can vary from person to person.

To get the most accurate results, follow these steps:

  • Take the pregnancy test on the first day of your missed period. This is when the placenta has started to produce hCG and the hormone will be present in your urine if you’re pregnant.
  • Take the test first thing in the morning. Your hCG levels will be at their highest in the morning, making it more likely for the test to detect the hormone.
  • Don’t drink too much. Drinking extra fluids can dilute your hCG levels and cause the test to fail.

Each test has different indicators for a “positive” or “negative” result, so make sure to read the package carefully to understand what the various results mean.

It’s possible to get a negative result on a pregnancy test but later find out from a doctor that you are, in fact, pregnant. There are a few reasons why this can happen, including testing too early or not following the instructions correctly.

What Can Cause a False-Negative Pregnancy Test?

Common Causes of a False Negative

Testing too Early

As mentioned earlier, taking a pregnancy test too early can lead to a false-negative result. It is recommended to wait until you have missed a period before taking a home pregnancy test for accurate results. However, if you suspect that you might be pregnant before your missed period, it is recommended to wait a few more days and retest.

Improper Testing

Improper testing can also lead to a false-negative pregnancy test result. It is important to read and follow the instructions on the pregnancy test kit carefully. Taking the test too early, not using first-morning urine, and not waiting long enough to read the results are common mistakes that can lead to inaccurate results.

Miscalculated Menstrual Cycle

Sometimes you may get confused about the first day of your period. It’s important to keep track of your menstrual cycle so you can figure out when your period is due to start. Women’s menstrual cycles can vary in length, but typically they last between 21 and 35 days.

If you don’t know your cycle, you might take a pregnancy test too early, before the levels of the pregnancy hormone hCG are high enough to detect. However, if you drink too much fluid before taking the test, it can dilute the hCG levels in your urine, leading to a false-negative result.

Too Much hCG in the Urine

On the other hand, if your hCG levels are too high, you may also get a false-negative result. This is rare, but it can happen if you take the test too late. Sometimes twin or higher order multiple pregnancies, in which levels of hCG are very high, can cause a false-negative pregnancy test. This is called the high-dose hook effect. Pregnancy tests are designed to detect a certain range of hCG in the body. If there’s too little or too much, the test may not work properly and you could get a false-negative result. So it’s important to take the test at the right time and to follow the instructions carefully.


Certain medications that contain hCG, such as fertility treatments, can cause a false-positive pregnancy test result. This includes some medicines given for infertility treatments—often called the “trigger shot” and sold under the brand names Novarel, Ovidrel, Pregnyl, and Profasi.

On the other hand, medications that affect hormone levels, such as birth control pills or hormone replacement therapy, can interfere with the accuracy of a pregnancy test and lead to a false-negative result.

Medical Conditions

Medical conditions that affect hormone levels, such as Polycystic Ovary Syndrome (PCOS) and thyroid disorders, can also cause a false-negative pregnancy test result.

PCOS is a common hormonal disorder that affects up to 10% of women of reproductive age. Women with PCOS have high levels of androgens (male hormones) and may experience irregular periods or no periods at all. In some cases, women with PCOS may ovulate later than expected, which can delay the rise of hCG levels and lead to a false-negative pregnancy test result.

Thyroid disorders, such as hypothyroidism or hyperthyroidism, can also affect hormone levels and interfere with the accuracy of a pregnancy test. Hypothyroidism, which occurs when the thyroid gland does not produce enough thyroid hormones, can cause a variety of symptoms, including fatigue, weight gain, and irregular periods. Hyperthyroidism, which occurs when the thyroid gland produces too much thyroid hormone, can cause symptoms such as weight loss, anxiety, and irregular periods.

Rare Causes of a False Negative

Ectopic pregnancy

In rare cases, a negative pregnancy test may indicate an ectopic pregnancy, which occurs when a fertilized egg implants outside of the uterus, usually in the fallopian tube. The fertilized egg doesn’t develop properly and can’t survive. This happens because the placenta, which is the organ that nourishes the developing fetus, doesn’t form correctly, causing a delay in the production of the pregnancy hormone hCG. If an ectopic pregnancy continues to grow, it can be dangerous and cause the fallopian tube to rupture. If you experience severe abdominal pain, vaginal bleeding, or dizziness, seek medical attention right away.

Gestational Trophoblastic Disease

Another reason why a pregnancy test might show a false negative is if you have gestational trophoblastic disease (GTD), which is also called a molar pregnancy. This is a rare condition in which a tumor develops from a fertilized egg. In some cases, a healthy baby can develop from a molar pregnancy, but in most cases, it results in a miscarriage.

GTD causes very high levels of the pregnancy hormone hCG. This can interfere with the accuracy of a home pregnancy test and give you a negative result even if you’re actually pregnant. While GTD is a type of tumor, it’s usually not cancerous. Treatment usually involves a procedure called a D&C to remove the abnormal tissue. In some cases, chemotherapy may be needed if the pregnancy hormone levels remain high after the procedure.

What to Do if You Have a late Period and Negative Pregnancy Tests?

If you haven’t gotten your period but your pregnancy test came back negative, there might be other reasons why your period is late besides being pregnant. There are a few things that can cause you to miss a period, like hormonal disorders (such as issues with your thyroid or high levels of prolactin), being underweight or overweight, certain chronic diseases, illness, travel, poor sleep, high stress, or excessive exercise.

If you don’t think any of these things are causing your late period, it might be a good idea to go to the doctor and get another pregnancy test. They can use a blood test which is more accurate and can detect lower levels of hCG (the hormone that indicates pregnancy) than a home pregnancy test.


Missing your period can be a bewildering experience, especially when your pregnancy test result comes back negative. But don’t worry, there are several plausible explanations. If you are not pregnant, it could simply be that your period is a little late. On the other hand, if you are pregnant, it may be too soon for the test to detect it accurately.

It is vital not to disregard any alarming symptoms, regardless of the cause. The earlier you seek medical attention, the quicker you will receive a proper diagnosis and treatment if needed.

Frequently Asked Questions

How Accurate are Home Pregnancy Tests?

Home pregnancy tests are highly accurate, with most brands claiming to have an accuracy rate of 99%. However, there are some factors that can affect the accuracy of the test, such as taking the test too early, using an expired test, or not following the instructions properly.

Can a Negative Pregnancy Test be Wrong?

Yes, a negative pregnancy test can be wrong. This can happen if you take the test too early or if you do not follow the instructions properly. In rare cases, a negative test result may also be due to a chemical pregnancy or an ectopic pregnancy, which may not show up on a home pregnancy test.

Can Exercise Cause a Late Period?

Yes, over-exercising can cause a delay in your period. This is because intense exercise can cause your body to produce less of the hormones that trigger ovulation.

How Long Should I Wait Before Taking a Pregnancy Test?

It is recommended to wait until you have missed your period before taking a home pregnancy test. If you take the test too early, it may not be accurate. However, some brands of pregnancy tests claim to be able to detect pregnancy a few days before a missed period, so it is important to read the instructions carefully.

What Should I do if I get a Negative Pregnancy Test But Still Think I Might be Pregnant?

If you get a negative pregnancy test but still think you might be pregnant, it is best to wait a few days and take another test. If you continue to get negative results and still have not gotten your period, it is a good idea to see a doctor. They may be able to perform a blood test or other tests to determine if you are pregnant.

What Other Factors can Affect the Accuracy of a Home Pregnancy Test?

In addition to taking the test too early or not following the instructions properly, other factors that can affect the accuracy of a home pregnancy test include medications that contain hCG (such as some fertility treatments), certain medical conditions (such as ovarian cysts), and drinking too much liquid before taking the test. It is important to read the instructions carefully and speak with a doctor if you have any questions or concerns.

How Long Should I Wait Before Seeing a Doctor About a Late Period?

If your period is more than a week late, it’s a good idea to see your doctor. They can help you determine the underlying cause of your late period and recommend appropriate treatment.

Disclaimer: Affiliate links used. We may earn a commission (at no cost to you) if you make a purchase.

Hi, I'm Sushil Singh, a devoted dad and guiding voice in the transformative journey of parenting, based in Mumbai. Drawing from a decade of firsthand experience and extensive research, I offer authentic insights into prepartum, pregnancy, and postpartum stages at Pregnancy Boss. From joyous milestones to challenging uncertainties, my mission is to provide reliable support and practical advice, helping you navigate this profound journey with confidence. Let's embrace the beauty and complexities of parenthood together. Connect for guidance or shared stories. Cheers to our shared path! 🥂 Social Medial Profiles: Quora Pinterest Twitter Facebook

Leave a Comment