Fear, impatience, a sense of inferiority, uncontrollable joy: how many emotions and moods follow each other when taking a pregnancy test. But can you really trust the tests you buy in every drugstore or even supermarket?
Which test should I choose?
The best home tests are those that are performed from the first day of a missed period, i.e. with medium sensitivity. Ultimately, the most “basic” tests are most often used in emergency care and have an accuracy of 90%. If you test too early, you risk getting a false negative result.
Although it is easy to perform a home pregnancy test, the results may not be as easy to interpret as expected. There should be two lines in the “window” confirming that the stork is flying, but one of them may be clear and the other may look like a light shadow. In case of an uncertain answer, if the lines are very light or the result is unclear, then to be sure, you can do a blood test in the laboratory of the Bogolyuby Medical Center . This test determines the amount of beta-hCG , a hormone produced by the embryo and ensuring its survival by delaying the regression of the corpus luteum and preventing menstruation. Thus, you can get the result on the same day if you are really impatient to get a definite answer. If you are not in a hurry, you can calmly wait a couple of days and then do the home test again.
When does a pregnancy test give a false result?
If the test is positive when conception has not actually occurred, it is called a false positive. Conversely, if the test shows only one line even after pregnancy has occurred, it is called a false negative.
False positives occur in rare cases, such as ovarian tumors that produce beta-hCG , which is actually produced by the placenta and is the hormone that pregnancy tests detect. Other possible causes of false positives include ovulation-stimulating drugs commonly used in assisted reproduction. However, in this case, labs performing the procedure are extremely careful not to test too early, risking detecting the beta-hCG drug dosage rather than a pregnancy.
A higher probability of a false-positive test is observed in women in the peri- and postmenopausal period . In these cases, the initial level of beta-hCG is higher than normal, and in very sensitive tests this can be interpreted as a sign of pregnancy. It is better to do a control test. Even after an abortion, a false-positive result can be detected 20-25 days after the termination of pregnancy.
Can a negative test become positive?
False negatives are more common than false positives – that’s a fact. And if in doubt, it’s wise to repeat the test in a few days. Conception could have occurred later than expected. With a regular cycle, ovulation occurs around day 14, and implantation of the fertilized egg occurs around day 21–22. But in the case of a long and irregular cycle, ovulation can occur after day 14, and therefore, the absence of menstruation on day 28 may not necessarily be associated with pregnancy.
Typically, an irregular cycle makes it difficult to determine the date of ovulation and, accordingly, the expected date of menstruation, conception and, therefore, the right time to take the test.
Highly sensitive tests that can detect pregnancy even before a missed period may be unreliable because the time of ovulation and possible conception were not correctly determined. To avoid a false negative result of this type, experts recommend waiting until the first day of a missed period. Using hormonal contraceptives or breastfeeding can also distort the situation.
