A quarter of women are believed to be unsure of the results of pregnancy tests. In fact, rapid tests are not so often mistaken. Should I trust them, “Doctor Peter” found out from the gynecologist of the Research Institute of Medical Mycology.
All rapid tests, regardless of price and method of operation, are based on one principle – they determine the presence of human chorionic gonadotropin in the urine (hCG). This is a hormone that begins to be produced in the female body 7-10 days after the fertilized egg begins to develop. It is believed that with the onset of pregnancy, hCG can be determined already in the first days of the delay of the menstrual cycle.
In tests, there are special substances that capture the hormone and react to it by changing the color on the strip or the appearance of the inscription on the screen of the electronic device: pregnant or nonpregnant (“pregnant” or “not pregnant”).
Why a false answer may be false
If the concentration of gonadotropin is insufficient, the test result may be a false negative. This can happen when conception occurred shortly before the onset of menstruation, and hCG has not yet managed to accumulate in a perceptible amount. By the way, with a period of more than 12 weeks, and the express test will also be useless: hCG ceases to be produced.
A false-negative test can be with an ectopic pregnancy and a threat of miscarriage. With excessive fluid intake, the concentration of hCG in the urine may also decrease, which means that the result of the analysis may turn out to be unreliable. Therefore, before the test, experts advise not to drink a lot of fluids and not to use diuretics. This is especially important in the short term when a woman does the test in the first days after the delay. And it’s best to determine your hormone level in the morning.
“On some tests, it is written that the time of day at which it is held does not matter,” says Yulia Dolgo-Saburova. – As a rule, such tests are positioned as highly sensitive. But no matter what the instructions say, a few days after the delay, I would still recommend doing the test in the morning, since a noticeable amount of hCG appears throughout the day in the urine around the third week of embryo development.
Why a positive answer may be false
In addition to false-negative results, rapid pregnancy tests may also show false positives. This happens when taking drugs containing hCG, for example, stimulate ovulation “Rotten” and “Profazi”. At the end of the course of treatment using these drugs, a high level of hCG may persist for up to two weeks. Therefore, the test will have to wait a while. After miscarriages, abortions, removal of an ectopic pregnancy, the hormone does not go away immediately – it remains in the body for some time, and tests can give false-positive answers.
To show pregnancy where it does not exist, the test can also be performed with various tumor processes.
How to avoid a mistake
In addition, false tests, both positive and negative, rapid tests can show for “technical” reasons.
The test may be poor or expired. Therefore, it is always necessary to check the expiration date, the tightness of the packaging and does not hesitate to ask for a certificate. You can use only a well-packed device and print it before direct use. Violation of storage conditions can also be misleading. In order not to doubt the correct storage of tests, it is better to buy them at a pharmacy.
Failure to comply with the test instructions and the use of stale urine can also change the result. But it often happens that on one day the test is positive, and after a while it becomes negative. But this is not a mistake. This happens when the pregnancy freezes at a very short time, and a miscarriage occurs. Usually, a woman does not notice him: everything happens like normal menstruation, only with a slight delay.
Three types of tests – three degrees of accuracy
There are three groups of rapid tests: test strips, tablets, and inkjets. The most popular of them are test strips. The principle of action is simple: you need to lower the test strip in a small amount of urine and after 5-10 minutes the answer will be known. If the second strip is colored – the test is positive, not colored – negative. It happens that the second strip changed color slightly, such a result is considered slightly positive. And gynecologists advise repeating the test in three days. Test strips are the cheapest, but also less “truthful” compared to the rest. The inaccuracy of the results is due to the fact that the strip can be underestimated or overexposed.
Tablet tests are somewhat more expensive, but it is believed that the quality of their results is higher. The test consists of two windows: In the first, you need to pipet a few drops of urine with a pipette, and in the second, after a while, the answer appears.
For jet tests, you do not need to collect urine separately – just substitute the device under the stream of urine, as indicated in the instructions. After a few minutes, the result will appear on the display. Inkjet tests are considered the most expensive, but also the most sensitive – with their help you can determine pregnancy even a few days before the start of the alleged menstruation.
No matter how you test, but you need to go for an ultrasound
– If a pregnancy test is carried out according to all the rules and there are no internal reasons in the body that could affect its reliability, it does not matter what type of tests a woman uses: in 99% of cases, you can trust him, says gynecologist Julia Dolgo- Saburova. – In my many years of practice, there were only two or three cases when the tests were wrong.
However, the only conclusive evidence of pregnancy is considered only ultrasound, which shows a fetal egg. And you can see it no earlier than a week after the delay.
If the pregnancy test is negative on the first or second day of the delay, the specialist advises to repeat it after 3 days. If it is positive, this is an undoubted reason to contact a gynecologist. If the test remains negative, it should be done in three more days. And if it turns out to be negative for the third time, and menstruation does not begin, you need to see a doctor as soon as possible.