A false-positive result refers to a pregnancy test that shows up as ‘positive’ even if you aren’t actually pregnant. This can be especially painful for women hoping to get pregnant or cause panic to women who aren’t. This can be a problem for a lot of cheap home pregnancy test kits; although they’re cheap, these home tests you can pick up in pharmacies aren’t the most accurate, and can in fact, produce false positives/negatives on a regular basis. So naturally, for the best, most accurate, 100% never wrong pregnancy tests, you need to go to the doctor, right?
Well, not quite.
How Do False Positives and False Negatives Happen?
For us to understand why false positives and negatives, we need to know how it happens and how pregnancy tests work in the first place.
Home pregnancy tests usually check urine for the hormone called hCg. hCg, or human chorionic gonadotropin, is a hormone produced by the female body during pregnancy. The body releases hCg via the placenta, which is formed when the fertilized egg attaches itself to the uterine lining. Blood tests can usually detect hCg levels in the body as early as 11 days after conception, while urine tests need around 12 to 14 days after conception for them to be effective. hCg levels in women usually double every 72 hours during the 8th to 11th week of pregnancy. After that, hCg levels remain constant and start to decrease only after the delivery of the baby.
The problem is, over-the-counter home pregnancy tests are only reliable if the instructions are followed to the letter, which is why more women prefer going to their OB-GYN. But can a urine pregnancy test at the doctor be wrong? Turns out, it can be.
Why Do False Positives and False Negatives Happen?
Most of the home pregnancy tests that are commercially available can be accurate if the instructions are followed properly; mean urine pregnancy tests at the doctors can also be 99-100% reliable IF proper protocol is followed.
Notice the similarities between pregnancy tests at home and at the doctors? Certain procedures need to be followed exactly, otherwise, they start producing false results. There are many factors that can lead to false results; even something as minor as leaving out a test result in the open air for too long can give you an inaccurate reading.
So can urine tests at the doctors be wrong? Well, some doctors might forget a step, or maybe go about it the wrong way. It doesn’t mean that your doctor is incompetent; they could be fatigued. After all, you’re probably not their only patient.
Here are some factors that can give your urine pregnancy test, whether at home or at the doctors, a false result:
The Test Was Left to Sit Out for Too Long
Standard urine pregnancy tests usually have indicators on them that show up if you’re pregnant: 1 line means that there is no pregnancy, while 2 lines indicate that the person is pregnant. However, these results must be checked within a specific time frame: leave the test out for too long, and there’s a chance that the urine will evaporate, making the other line disappear; or, alternatively, the urine will evaporate leaving a mark, which many people mistake for a second line.
This can also happen during a urine pregnancy test at the doctors. Often, it’s because the doctor is prepping another test, chatting with the patient, or filing paperwork. Avoid this by following the length of time given by the pregnancy test in order to produce as accurate a result as possible.
The Pregnancy Test Being Used is Expired or Contaminated
One of the most overlooked reasons for getting false results is using expired or contaminated urine pregnancy tests. Most people aren’t even aware that pregnancy tests have an expiry date, leading them to (falsely) assume that they can use old or expired pregnancy tests.
Contaminated pregnancy tests, on the other hand, can also give inaccurate results. Bacterial growth on the activation strip can skew the way the test detects hCg, giving either false positives or negatives. To avoid this, always make sure that the pregnancy test you’re using at home or at the doctor’s is well before its expiry date, and that the test itself is clean and sealed inside the packaging.
Fertility Medications can Temporarily Raise hCg Levels in Women
In Vitro fertilization and other fertility treatments often require the woman to take medications that raise certain hormones that make their bodies more susceptible to pregnancy. These drugs often contain high amounts of artificial hCg, as it’s an effective way to convince your body to be more receptive to conception.
Taking a urine pregnancy test too soon after taking fertility medication can definitely give out a false positive result, thanks to the presence of excessive artificial hCg.
Your Body Experienced a Miscarriage Very Early On in the Pregnancy
Unfortunately, one of the reasons why a pregnancy test might provide a false positive is also one of the most devastating: the test wasn’t wrong per se, your body just underwent an extremely early miscarriage.
Most miscarriages happen within the first 13 weeks, or 3 months, of pregnancy (although this is not a hard rule, as everybody is different). If a miscarriage happens within the first 13 weeks, this is called a chemical pregnancy. Chemical pregnancies are short pregnancies that occur when the fertilized egg is lost shortly after it has been implanted. Often, the cause for this is due to certain chemical imbalances or hormonal abnormalities within the fertilized egg. It’s one of the most common causes of miscarriages, with chemical pregnancies accounting for up to 75% of miscarriages within the first trimester.
Women who take a urine pregnancy test before their early miscarriage aren’t actually getting a false positive: the test results were, in fact, very accurate, it’s just that circumstances beyond anyone’s control resulted in the body rejecting the fertilized egg. Unfortunately, this is a common problem, with 1 in 4 recognized pregnancies experiencing a miscarriage, 85% of which happening during the first 13 weeks.
Chemical pregnancies are usually hard to detect because, while the woman will often experience some form of bleeding during their miscarriage, it will often happen during their expected period days, leading many to assume that it is just regular period discharge.
It’s Still Best to Consult a Doctor
Yes, urine pregnancy tests at the doctor’s can still be wrong, but this is often very rare; 9 times out of 10, it’s best to confirm any home pregnancy test results with your designated Ob-Gyn, as they have the necessary experience and equipment to confirm home pregnancy test results. Make sure, however, to take pregnancy tests more than once, so as to completely rule out the possibility of a false or inaccurate result.