Pregnancy can be detected by testing the HCG level in the blood through a venous blood sample 4 days after menstruation. If the fertilized egg is early, a weak positive result can be detected by the early pregnancy test, but if the fertilized egg is late, pregnancy cannot be detected by the early pregnancy test. If the fertilized egg is late, the early pregnancy test will not detect pregnancy. It is recommended that the test result is more accurate when the early pregnancy test is more than 7-10 days after normal menstruation. If the period is more than 4 days, if the early pregnancy test is negative, it is recommended to test again after 3 days or directly through venous blood to detect pregnancy if the period never comes. If you have a normal sexual life without contraceptive measures, it is more likely to be pregnant after 4 days of menstruation. Women of childbearing age who have a normal sexual life and have delayed menstruation are advised to rule out early pregnancy first.