If the period is absent and certainty about a possible pregnancy is to be obtained, a pregnancy test is used. This indicates whether the pregnancy hormone hCG is present. Modern pregnancy tests are very reliable with a laboratory accuracy of over 99.9%.
What is a pregnancy test?
To make sure that a pregnancy is actually present, the presence of the pregnancy-sustaining hormone hCG in the urine is often tested. A pregnancy test is a test with the help of which one can clarify from home without medical intervention whether fertilization and implantation of an egg – and thus a pregnancy – has occurred. A commercial pregnancy test is used with the morning urine. One can buy such tests both in the pharmacy and in drugstores. Cheap pregnancy tests are available from about four euros, in Internet stores sometimes even cheaper.
Function, effect and goals
Application area of a pregnancy test is the clarification of whether a pregnancy has occurred in the past cycle. A pregnancy test can be performed by the woman herself or in a doctor’s office. The procedure used by a pregnancy test is the same for both home tests and tests performed in a doctor’s office:
The test measures whether the hormone hCG can be detected. hCG is a hormone produced exclusively by pregnant women. If hCG is detected, the test is considered positive. It can then be assumed that a fertilized egg has nested and thus connected to the maternal bloodstream. The application of a pregnancy test is simple. The test stick is taken out of the packaging. Now the test area of the stick must come into contact with urine. Ideally, morning urine is used for this purpose, as it has the highest concentration of hCG. You can either moisten the test stick with urine directly during urination or collect urine in a sterile container and then dip the stick. The time for which the test stick should be held in the urine is defined by the manufacturer. In most cases it is 10 seconds. This time should be adhered to during use in order to achieve the most reliable result possible. After a few seconds, the result can usually be read. Most tests are designed in such a way that a second line forms in the result window if hCG was detected. Digital tests also measure whether hCG is present and display the word “pregnant” in the result window if hCG is present. Such digital tests are usually somewhat more expensive. A special form of pregnancy test is the blood test. hCG can be detected not only in urine, but also in blood. For this purpose, blood is taken from a vein in the woman’s arm and tested for hCG in the laboratory. Such a procedure is not suitable for home use and is also clearly inferior in the evaluation of a practical pregnancy test using urine. A blood test as a pregnancy test is usually performed by fertility centers. A fertility clinic often performs a pregnancy test at a very early stage. In blood hcg is detectable earlier than in urine. The urine value lags behind the blood value in about 48 hours. In this respect, the woman has a result at a very early period about whether hcg could be detected or not.
Risks and dangers
A pregnancy test does not pose a health risk for the woman. Especially with a urine test, there can be no side effects or injuries. The blood test as a pregnancy test carries at least the theoretical risk of injury or infection of the puncture site due to the collection of blood from the vein. A more mental risk is the possible error of a pregnancy test. In principle, with laboratory accuracies of more than 99.9%, a very high reliability of the tests can be assumed – provided that they are handled correctly. This also includes choosing the right time for a pregnancy test. Most pregnancy tests are supposed to be reliable from the time of the missed period. However, since the physical rhythm is not always absolutely predictable, it is not possible to predict with absolute accuracy when the period would be due.On the one hand, a test that is performed too early can give a false negative result, because despite implantation of the egg, there was simply not enough hcg present. However, those who use a very sensitive pregnancy test very early can also be disappointed: Especially in the first days of pregnancy, there is very often a natural loss of the egg. Without a pregnancy test, this usually goes completely unnoticed by women.
