Statistically, 25% women are not sure about pregnancy test results. In fact, express pregnancy tests don’t fail so often. But can you trust their results without any doubts? Or can a pregnancy test be wrong?
All the express-tests, regardless of their costs and working methods, are based on the same principle – they detect human chorionic gonadotropin (hCG) in urine. The female body begins to produce this hormone on the 7th-10th day after the fertilized egg cell starts developing. It is considered possible to detect hCG during the first few days after a missed period in pregnancy.
The tests contain specific substances that are able to detect the hormone and react to it by changing color or by the identification appearing on the digital screen (pregnant or not pregnant).
Why can a pregnancy test be false-negative?
If the concentration of human chorionic gonadotropin is too low the test results can be false-negative. It happens when the conception occurs not long before the usual period and a sufficient amount of hCG hasn’t accumulated in the organism. By the way, if the term of pregnancy is more than 12 weeks a pregnancy test also becomes useless: the production of hCG stops.
A false-negative test may be a sign of an ectopic pregnancy or a possible miscarriage. High intake of liquids also lowers the hCG concentration in urine – that means the test results can be inaccurate. That’s why medical experts advise not to drink much liquid or take diuretics before the test. It’s especially important to observe this rule in the early stages of pregnancy when a woman is doing the test during the first few days after a missed period. It’s better to identify the hormonal level in the morning.
Some pregnancy tests have a label that says it doesn’t matter which time of the day you’re going to use them. As a rule, such tests are called “high-sensitive”. But no matter what the instruction says, in the first few days after a missed period health professionals recommend using the pregnancy test in the morning because a detectable during the whole day amount of the hCG hormone appears in urine only by the third week of fetal development.
Why can a pregnancy test be false-positive?
Besides the false-negative results, express pregnancy tests can also show false-positive ones. This can happen after the intake of medications containing hCG, for example, ovulation stimulators. By the end of a course of treatment such medications can keep the hCG level high during a period of time up to two weeks. So, you’d better wait for two weeks before doing a pregnancy test.
After a miscarriage, abortion or removal of an ectopic pregnancy the hormone doesn’t leave your body immediately – it remains in the organism for some time, so pregnancy tests show false-positive results.
An express-test can also be wrong and show you’re pregnant when you’re indeed not if you have a tumor.
Can a pregnancy test be wrong – how to avoid errors
In addition to the aforementioned information, a pregnancy test can show incorrect results, positive as well as negative, because of “technical malfunctions”.
You can buy an expired or defective pregnancy test. That’s why you should always check the expiration date, the integrity of the cover, and the manufacturer’s certificate when buying a test. Only a well-packed test will be of use, and you should open it immediately before application. The test can be wrong because of improper storage conditions. If you want to get a trustworthy result, buy a test in a drugstore.
Disregard of the instructions or stale urine can change the result as well. But a more common occurrence is the pregnancy test one day being positive, and after a bit of time – negative. It’s not a mistake. It happens when your pregnancy ends in the early terms and then there’s a miscarriage. It usually goes unnoticed by a woman: everything looks like a normal menstruation with only a short-term delay.
Three kinds of pregnancy tests – three degrees of accuracy
There are three types of express-tests. All of them you can buy over the counter anytime. The most popular pregnancy tests require a woman to collect a urine sample into a small cup and put the stick into it – you’ll find out the answer after a few minutes. If the second line appeared the test is positive, if not – the result is negative. In some cases the second line is faint: such a result is considered faint-positive. And gynecologists recommend doing another pregnancy test after three days since the first one. Such sticks are the cheapest and the least accurate in comparison with other express-tests. The results are imprecise because you can miscalculate the time and wait for too long or not long enough.
The second type of express-test requires a woman to collect a urine sample and then with a dropper put a few drops of the urine into a special container. These pregnancy tests are more expensive, but their results are more precise.
The third kind of tests doesn’t require collecting a sample into a cup – you can just hold a stick under the urine stream as the instruction tells. After a few minutes you’ll find out the result on a display. These pregnancy tests are the most expensive and the most sensitive – they make it possible to detect pregnancy even a few days before the next estimated menstruation.
Can a pregnancy test be wrong? Don’t worry – do a pelvic ultrasound!
If a pregnancy test is used correctly and there are no other reasons for it to be faulty you can believe its results in 99% of cases. However, the infallible proof that a woman is expecting is the pelvic ultrasound which shows the fetal bladder. It’s possible for an expert to see it a week after a missed period at least.
If on the first-second day of a missed period the pregnancy test shows a negative result, medical experts advise repeating it in three days. If you’ve got a positive result – it’s definitely a good reason for visiting a gynecologist. But if the test remains negative you should repeat it after another three days. The third negative test and the absence of a menstruation should be enough for you to suspect a health problem and immediately visit your doctor.