The pregnancy test is a test for human chorionic gonadotropin, a hormone that is secreted by the cells of the embryonic trophectoderm in the early stages of pregnancy. If the color of the pregnancy test deepens, it means that the hormone level is being secreted more and more in the body, but it does not mean that it is doubling. However, it does not mean that the hormone level has doubled because the doubling has to be proved by numbers, that is, the number of the second test is twice the number of the first test. If you want to know if it is doubling, you can only go to the hospital to have a blood test to check the concentration of HCG in the blood. If the concentration of HCG in the blood doubles after 48 hours, it means that the baby is developing well.