The presence of pregnancy is established by detecting the hormone hCG (chorionic gonadotropin), produced in the body of a woman after the embryo is attached to the uterus. This hormone is produced to block the natural function of the ovaries and prevent re-pregnancy.
In the early stages, the female body produces this hormone in small quantities, so the test is recommended to be done no earlier than a few days from the day of the delay.
There are frequent cases when a woman does not know the exact date of the onset of menstruation due to their irregular course, as well as situations when the test gives a negative result, while processes are taking place in the body that in all respects resemble signs of pregnancy.
In such cases, it is recommended to visit specialized institutions for taking a blood test to determine the level of the hCG hormone. In this way, pregnancy can be determined even before the onset of a delay in menstruation, since this hormone enters the bloodstream much faster.
Test strips sold in retail pharmacies often give incorrect results, because they are not very sensitive, but show the result only from a certain amount of the hormone contained in the blood. It enters the blood slowly, so a test made in the first days may show an incorrect negative result, due to the fact that a sufficient amount of the substance has not yet been produced in the body.
In the presence of pregnancy, this number increases daily, therefore, with a negative indicator, it is recommended to repeat the test after a few days. The test strip shows the most accurate result on the 15th day from the day of ovulation, so it is important to know the exact or estimated date from ovulation, which will help you understand when to take the test.
Doctors say that the hormone reaches its maximum at the 8th week of pregnancy and this level lasts until the 12th week, after which it begins to slowly fall. If the pregnancy is multiple, then this figure doubles accordingly. If at 3-6 weeks the level of hCG is less than normal, then this may indicate a likely risk of spontaneous miscarriage of the embryo.