Pregnancy can be detected in as little as 21-24 days. The egg combines with the sperm to form a fertilized egg, and the trophoblast cells begin to secrete human chorionic gonadotropin on the 6th day after the fertilized egg has been deposited in the uterine cavity, which can be detected in the blood about 1 day later. Women who do not use contraception after intercourse during ovulation can draw blood to detect pregnancy as early as 7 days, i.e., 21-24 days of pregnancy, and the method of detecting pregnancy is the earliest, most sensitive and most accurate. Usually test whether pregnancy is usually in the menstrual delay 7 days did not come to draw blood tests or use early pregnancy test paper test, early pregnancy test paper test to be later than the blood test. Due to the test paper and individual differences, the test whether to use morning urine can be detected at the time of pregnancy there are differences, you can go to the hospital line for further examination, to avoid the occurrence of ectopic pregnancy.