Why am i getting negative and positive pregnancy test

No matter what, taking a pregnancy test can be an emotional roller coaster. When it comes to getting a false positive pregnancy test result, the experience can be deeply upsetting, particularly for anyone who has had a difficult time getting pregnant or is actively hoping to get pregnant (or both). The hope that comes with seeing that positive sign crashing down as you realize it was a false positive pregnancy test? It's a uniquely devastating emotion. 

Of course, getting a false positive pregnancy test when you’re actively trying not to get pregnant can be just as horrible. Yup, you could probably do without the panicked verification trip to the ob-gyn, just to learn there was nothing to stress over. 

Thankfully, experts note that false positive pregnancy tests are rare. Unfortunately, though, they can happen. Here are some of the most common causes of a false positive pregnancy test, along with some additional information that can help you put it all into context.

First, what is a pregnancy test?

Let's start with the absolute basics just to make sure we're all on the same page. A pregnancy test tells you if you’re pregnant or not. That's simple enough to understand. But it's understandable if you're a little fuzzy on the details of what these devices actually look for to identify a pregnancy.

At-home pregnancy tests check for the hormone hCG. HCG is short for human chorionic gonadotropin, which the body creates during pregnancy. Right after a fertilized egg attaches to the uterine lining, the placenta then forms and starts producing hCG1. A blood test can detect hCG about nine days after conception, and a urine test can detect it 12 to 14 days after conception, according to the Cleveland Clinic, although it varies—some especially sensitive urine tests can detect a pregnancy even earlier. A person’s hCG level typically doubles every 72 hours through 8 to 11 weeks of pregnancy. Then it remains consistent and starts to go down after delivery.

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How does a pregnancy test work?

An at-home pregnancy test is designed to find hCG in pee2. If the hormone is present, it triggers a chemical reaction and the test signals that you're pregnant. If hCG is not present, the test will say you aren't pregnant. Many tests use two lines to mean you’re pregnant and one line to mean you’re not—but it depends on the test brand. Some tests use plus and minus signs. Some digital pregnancy tests have a screen that plainly reads "pregnant" or "not pregnant." Which can save you some “Is that one line or two?!” squinting, at least.

Seems simple, right? As Ina Garten would say, "How easy is that?" Typically, pretty easy. Most at-home pregnancy tests claim to be about 99% accurate3. Ultrasounds typically can't detect a pregnancy until a little later in your pregnancy and that's why at-home tests are so useful. But, sometimes, other elements can mess with a pregnancy test's results and tell you you’re pregnant when you’re really not. 

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What can cause a false positive pregnancy test?

Here are the most likely reasons you may end up with a false positive pregnancy test:

1. You let the test sit too long before looking.

If you take a standard pregnancy test with line indicators, it's important to check the results according to the specific instruction of the test. If you let it sit too long before reading the results, urine on the test can evaporate and make it look like you have two lines instead of just one. "Oftentimes people will see evaporation lines as urine starts to evaporate off the test," Jamil Abdur-Rahman, M.D., board-certified ob-gyn, tells SELF. That might cause the test to look like it has a faint second line—making it positive—but it really only has one.

The best way to avoid this: Read the pregnancy test's directions and follow them exactly. The popular pregnancy test brand First Response, for example, instructs users to wait three minutes after taking the test, then read it as soon as possible4.

2. The pregnancy test is expired.

The second most common reason Dr. Abdur-Rahman's patients get false positives is because the test is expired, he says. When a test is past its expiration date, the chemical that detects hCG doesn't always work as it should, and you’re more likely to get a misread. "The test can expire and the chance of having a false positive increases," Dr. Abdur-Rahman says.

3. You’re on fertility medications that raise hCG levels.

If you take a pregnancy test too soon after taking a fertility drug that contains hCG—like some injections that are often part of in vitro fertilization—you could get a false positive.

Pregnancy tests hold a lot of weight. With one positive test, your entire life will change. But what about when a test comes back falsely-positive? A false-positive test result only happens less than 1% of the time, but when it does, it can make the following days or weeks confusing before you realize you’re not actually pregnant.

So what actually causes a false-positive test and how do you decrease the chances of it happening to you? We’ll cover the top reasons for false-positive pregnancy tests below, but if you’d like to learn more about how tests work, click here.

False Pregnancy Test Results

In some cases, tests offer a false result. But, in other cases, they detect the presence of an embryo, even if the pregnancy is not viable. For the first five points below, we’ll cover false results where the test detects elevated hCG (the pregnancy hormone) and indicates a pregnancy that does not exist. The final two points, we’ll cover instances when the test accurately detects hCGs in a pregnancy that is not viable.

1. You Had A Miscarriage or Abortion Recently

After an embryo implants , it begins to secrete human chorionic gonadotropin (hCG), the pregnancy hormone. HCG is produced by the cells surrounding a growing embryo. The presence of hCG triggers a positive test result.

After an abortion or miscarriage, hCG levels start to go down  over the a period of 9-35 days. If you take a pregnancy test within this window, you can get a false-positive result because the test is still detecting the pregnancy hormone and can’t tell that the levels are decreasing.

2. Some Medications Can Trigger False-Positives

If a woman is having a hard time getting pregnant, her doctor may put her on fertility treatments. Some of those medicines include hCG which helps follicles release mature eggs within a woman’s ovary. If a pregnancy test is taken within 7-14 days after fertility treatments, a false-positive can occur. It is recommended to delay pregnancy testing until 1-2 weeks after the last injection or treatment.

Tell your doctor if you’re taking any medication because various medicines can trigger false-positives. Once your physician knows what you’re taking, he or she  can help you with over-the-counter test results.

3. Medical Conditions Are Sometimes to Blame

Sometimes medical conditions can trigger a false-positive in urine tests. If you have any of the following, they might inflate your hCG levels and you might get a false-positive:
* Ovarian cysts
* Kidney disease
* Urinary tract infection
* Pituitary problems
* And in some cases, ovarian cancer and other serious diseases

If you get a false-positive test result and have ruled out other causes, consult a medical professional to test for these conditions. Your doctor may recommend a blood test to get a more accurate test result.

4. Confusing Evaporation Lines

If the pregnancy test instructions were not followed precisely, sometimes an evaporation line can be mistaken for a positive. Many tests show two lines when hCG is detected and one line when hCG isn’t detected, or a plus or minus sign.

For the line tests, sometimes, a faint-colored second line appears. This may represent an early pregnancy or may simply be an evaporation line.

If you read the test after the recommended time in the instructions, the results might be a false-positive since the evaporation line may show up more clearly. Avoid any confusion by following the test’s timing directions exactly as they’re written. Each test brand has specific instructions, so follow them closely.

5. User Error

Like most consumer goods, pregnancy tests expire and are sometimes used wrong. Using a test incorrectly or using an old one can lead to a false-positive result. Here are a few tips to avoid user error:

* Before using your test, check the use-by date and follow the instructions closely.
* Use the tests when your urine is concentrated like when you wake up in the morning. Diluted urine from excessive water-drinking can affect the accuracy of the test.
* Avoid using a test too early in your menstrual cycle.
* Leave the dip-stick in your urine stream for the exact amount of time required by the instructions. Set a timer to keep track.
* Set another timer to check your results in the correct time frame outlined in the instructions.

Technically-Positive Pregnancy Test Results

The next two points are unique in that they indicate the presence of BhCG in the body so they are technically accurate in giving a positive result. However, an ectopic or chemical pregnancy sadly is not viable.

6. An Ectopic Pregnancy

When an embryo implants itself outside the uterus , it’s known as an ectopic pregnancy. Almost all ectopic pregnancies—more than 90%—happen in a fallopian tube. As the pregnancy grows, it can cause the tube to burst (rupture). A rupture can cause major internal bleeding. This can be a life-threatening emergency that needs surgery.

Even though the embryo isn’t viable it will still produce hCG, triggering a positive pregnancy test.

If you think you have an ectopic pregnancy, or have a positive pregnancy test paired with severe pain on one side of the lower abdomen and spotting, seek immediate medical help as soon as possible.

7. A Chemical Pregnancy

A chemical pregnancy is a miscarriage that happens before week five of the pregnancy when an embryo implants in your uterus but it never takes hold. The loss happens so early that you may not even know you're pregnant. However, the embryo produces hCG and can cause a false-positive on a pregnancy test. This situation is known as a chemical pregnancy.

Chemical pregnancies aren’t a result of action or inaction by the woman but can occur because of:
* Fibroids
* Scar tissue
* Low amounts of certain hormones like progesterone
* An irregular-shaped uterus

The emotional strain from false-positive results can be severe and mentally taxing for you and your family. We recommend waiting to use at-home pregnancy tests until one week after the expected start of your period.

We also recommend getting a confirmed diagnosis at a local clinic or with your healthcare provider. You can always book a 30-minute appointment for a free pregnancy test at The Source clinic nearest you. Click the button below to schedule a free appointment today.

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