If pregnancy is confirmed and cannot be detected by pregnancy test, it means that the quality of the pregnancy test is not good or the pregnancy time is relatively short and the concentration of hCG in urine is low, because the test of pregnancy test is not very sensitive and the pregnancy test will only detect it after the hCG in blood reaches a certain concentration and is discharged from urine. Therefore, to determine if you are pregnant, it is best to go to the hospital for blood tests. hCG in the blood will rise on the 7th day after fertilization, and if it appears to rise, you can be sure that you are pregnant, and if you are normally pregnant, hCG will double after 48 hours, after which regular pregnancy tests can be done.