Pregnancy can usually be detected by blood HCG test after 7 days of intercourse, which may take about 10 days if using pregnancy test paper or 21 days if using ultrasound. If a woman forms a fertilized egg after intercourse, the fertilized egg will produce human chorionic gonadotropin (HCG) when it settles on the bed, and it is usually possible to tell if you are pregnant by testing the HCG in your blood about 7 days after intercourse, and by testing the HCG in your urine about 10 days after intercourse. If an ultrasound test is performed, it usually takes about 21 days after intercourse to detect the pregnancy. If a woman detects pregnancy after intercourse, she must follow the doctor’s instructions to do a good job of care, and at the same time, rest, not to be tired, do not do heavy physical work, but also pay attention to balanced nutrition, if there is any discomfort during pregnancy, go to the hospital in time to see a doctor.