It can be detected about 15 days after intercourse with an early pregnancy test, but there are individual differences. If a woman who wishes to have children has intercourse during ovulation, the trophoblast cells begin to secrete HCG (human chorionic gonadotropin) about 1 day after the fertilized egg has laid, and a blood HCG test is used to determine if she is pregnant about 15 days after intercourse. Women who are preparing for pregnancy, whether detected by blood HCG or pregnancy test, should follow the doctor’s instructions to have an ultrasound examination at about 40 days after menopause to confirm a normal intrauterine pregnancy. In addition, if the diagnosis of pregnancy is clear, early pregnancy should also pay attention to appropriate rest, avoid exertion, strenuous exercise and stay up all night, eat a light diet, and follow the doctor’s advice to continue to take folic acid on time.