It takes about 15 days after sexual intercourse to detect if you are pregnant, and you will need to have a blood test for HCG to detect it. If you want to test with an early pregnancy test, you can only detect pregnancy about 18 days after intercourse. The fertilized egg does not enter the uterine cavity immediately, but takes about 14 days on average before it enters the uterine cavity, and after it enters the uterine cavity, the fertilized egg does not settle in the uterine cavity immediately, but has to be free for 2-3 days before it settles, and only then does it secrete blood HCG. This is when the pregnancy can be detected by a urine or blood test. Therefore, it takes about 15 days after intercourse to detect pregnancy. Since blood HCG appears positive earlier than urine HCG, blood HCG can be detected 1-2 days after menopause, while urine HCG can be detected 5-7 days after menopause.