This hormone begins to be produced in the female body after implantation of the embryo into the uterine wall. On day 7-8, after conception, the secretion of this hormone can be detected in the urine. So, if you suspect the pregnancy, feel free to use the test without waiting for the date of the expected menstruation.
The level of hCG in the blood allows you to find out the approximate age of the fetus. With multiple pregnancies, the level of the hormone in the blood increases in proportion to the number of fetuses.