It is not possible to detect pregnancy after 1 week of intercourse. Because the fertilized egg has not yet entered the uterine cavity for implantation, only after implantation will the trophoblast cells secrete blood HCG, and only then can pregnancy be detected by blood sampling, so it is recommended to test for pregnancy by blood sampling 15 days after intercourse. In addition, if you want to use the morning urine to check if you are pregnant, it is recommended to collect the morning urine again 20 days after intercourse and test for HCG, which can also detect whether you are pregnant. If there are two red lines indicating pregnancy, if there is one red line indicating no pregnancy, if there are two red lines, one dark and one light, indicating possible pregnancy, it is recommended to test again after 3 days.