Can a Pregnancy Test Be Wrong?

Taking a pregnancy test can be a nerve-wracking experience, especially if you're anxiously hoping for a specific result. Whether you're trying to conceive or worried about an unplanned pregnancy, a simple test line can spark a whirlwind of emotions. But what happens if the result is wrong? Can you truly trust a home pregnancy test? The short answer is: pregnancy tests are highly accurate when used correctly—but yes, they can sometimes be wrong. In this post, we’ll dive into how pregnancy tests work, the common reasons for false results, and what to do if you suspect your test result is inaccurate. We’ll also explore how to maximize your chances of getting a reliable result.

How Do Pregnancy Tests Work?

Basic Explanation

Home pregnancy tests work by detecting human chorionic gonadotropin (hCG), a hormone produced shortly after a fertilized egg attaches to the uterine lining. This hormone is present in the urine and increases rapidly in early pregnancy. Most over-the-counter tests—including strips, midstream tests, and digital versions—are designed to detect hCG and indicate a positive or negative result.

Timing and Accuracy

The timing of the test plays a major role in accuracy. After conception, it can take 6 to 12 days for the fertilized egg to implant in the uterus, and only then does hCG start to rise. For most people, hCG levels are high enough to detect about 10–14 days after ovulation. That’s why it’s generally recommended to test after a missed period for more reliable results.

MomMed Pregnancy Test Strips are known for their high sensitivity (25 mIU/mL), helping to detect even early levels of hCG with over 99% accuracy when used correctly and at the right time.

Types of Incorrect Results: False Positives and False Negatives

False Positive

A false positive means the test shows you’re pregnant when you’re not. While rare, this can happen due to:

• A recent miscarriage or abortion (hCG can linger)
  
• Certain medications containing hCG
  
• Medical conditions like ovarian cysts or rare tumors
  
• Chemical pregnancies, where early miscarriage occurs before symptoms
  

False positives are far less common than false negatives but can be emotionally distressing if you're not expecting one.

False Negative

A false negative occurs when you’re actually pregnant, but the test says you're not. This is far more common and often results from:

• Testing too early (before hCG has built up)
  
• Diluted urine (e.g., after drinking a lot of fluids)
  
• Low-sensitivity tests
  
• Not following test instructions properly
  

Using a sensitive and easy-to-read pregnancy test, especially first thing in the morning when hCG concentration is highest, helps reduce the chance of a false negative.

When Are Pregnancy Tests Most Accurate?

Timing

For most people, pregnancy tests are most accurate when taken after a missed period. This is because hCG levels rise significantly after implantation, which typically occurs 6–12 days after ovulation. If your menstrual cycle is regular, testing around 14 days post-ovulation (DPO) gives the best chance of detecting pregnancy with over 99% accuracy.

However, if your cycle is irregular or you’re unsure when ovulation happened, it’s safer to wait at least 21 days after unprotected sex. Early detection tests can sometimes pick up hCG earlier, but waiting a bit longer helps minimize the chances of a false negative.

Morning Tests

Using your first-morning urine (FMU) increases accuracy, especially during early pregnancy when hCG levels may still be low. FMU is typically more concentrated, offering a better chance of detection. If you must test later in the day, try to limit fluid intake for a few hours beforehand to avoid diluting your urine.

Avoid Testing Too Early

Many people are eager to test before their missed period, especially when they're tracking ovulation and know their DPO. But testing too early often leads to disappointment—even if you’re pregnant—because hCG hasn’t built up enough yet. If you test early and get a negative result, don’t panic. Wait a few more days and test again.

Pro tip: If you're using ovulation test strips like MomMed Ovulation Test Strips, you can pinpoint your ovulation day more precisely, which helps you calculate the best day to take your pregnancy test for accurate results.

Common Mistakes That Lead to Wrong Results

Testing Too Early

Testing before hCG levels have built up enough in your urine is one of the most common reasons for a false negative. Even though some tests claim to detect pregnancy days before a missed period, the results can still be unreliable. Waiting just a few extra days can make a big difference.

Not Following the Instructions

Every pregnancy test brand is slightly different. Some require dipping the strip for 5 seconds; others need a full 10 seconds. Some results must be read within 3 minutes, others at 5. Misreading or skipping these directions increases the risk of error. Always read the full instructions, even if you’ve used other tests before.

Using Expired or Damaged Tests

Pregnancy tests don’t last forever. If the chemicals in the test degrade due to age or improper storage, the test may not detect hCG reliably. Always check the expiration date before use, and avoid tests that have been exposed to moisture, heat, or damaged packaging.

Improper Storage

Keeping your test in a humid bathroom or a car’s glove compartment can reduce its accuracy. Tests should be stored in a cool, dry place at room temperature. Also, avoid removing them from their foil wrapper until you’re ready to use them.

What to Do If You Get a Wrong Result

Retest in a Few Days

If you suspect your pregnancy test result is wrong—especially if it was negative but your period still hasn’t arrived—it’s best to wait 2–3 days and test again. hCG levels double approximately every 48–72 hours in early pregnancy, so a second test may give you a clearer answer. Be sure to use first-morning urine for the most accurate result, and choose a high-sensitivity test for early detection.

Check the Instructions

Misreading or skipping steps in the instructions is a surprisingly common reason for wrong results. Go back and review the steps you followed, and compare them with the instructions provided with your specific test. Did you wait the correct amount of time? Did you use the right amount of urine? If in doubt, follow the instructions again with a new test.

Consult Your Doctor

If you continue to get unclear or conflicting results—such as faint lines that don’t get darker, or repeated negatives despite pregnancy symptoms—it’s time to see a healthcare provider. They can perform a quantitative blood test to measure your exact hCG levels, which is far more sensitive than any home test. Your doctor may also check for other conditions that could be causing a delayed period or pregnancy-like symptoms.

Track Your Cycle for More Clarity

If you’ve been guessing your ovulation date, try tracking it more precisely next time. Using MomMed Ovulation and Pregnancy Test Strips Kit can help you identify your fertile window, which in turn helps you know when to test for pregnancy with greater confidence and accuracy.

When to Consult a Healthcare Provider

Persistent Symptoms

If you’ve taken one or more negative tests but are still experiencing strong pregnancy symptoms—like nausea, breast tenderness, fatigue, or a missed period—it’s important to schedule a medical appointment. Some people have low hCG levels early on, or irregular cycles that make home testing tricky. A doctor can help clarify what’s going on.

Blood Test

Blood tests can detect even very low levels of hCG and provide quantitative results—meaning they tell you exactly how much hCG is in your system. This is useful not only to confirm pregnancy but also to track whether your hCG levels are rising as expected. These tests are typically performed in a clinic and results are available within a day or two.

Ultrasound

If there’s still uncertainty after blood tests, your provider may recommend an ultrasound, especially if you’re already a few weeks into your cycle. An early ultrasound can confirm a pregnancy, detect multiple embryos (in the case of twins), or rule out other causes of symptoms such as ovarian cysts or an ectopic pregnancy.

Conclusion

While home pregnancy tests are highly reliable—especially high-quality ones like MomMed Pregnancy Test Strips—they aren’t completely foolproof. Factors like timing, usage errors, and even storage conditions can impact the accuracy of your results. False positives are rare, but false negatives are more common, especially if you test too early. That’s why understanding how these tests work and how to use them properly is key to getting the answers you need. If you’re ever in doubt, retest after a few days or consult a healthcare provider for peace of mind. And if you're trying to conceive, pairing your pregnancy tests with MomMed Ovulation Test Strips can help you track your cycle and improve your chances of timely and accurate testing.