The intrauterine gestational sac is not yet visible on the 10th day of pregnancy and can usually be seen at about 35 days after menopause. The trophoblast cells begin to secrete HCG (human chorionic gonadotropin) about 1 day after the fertilized egg is deposited in the uterus, and the earliest way to tell if you are pregnant is to test for HCG levels about 10 days after intercourse. However, the intrauterine gestational sac cannot be seen by ultrasound on the 10th day of pregnancy, and can usually be seen on ultrasound around 35 days after menopause, making it clear that the pregnancy is normal. Early pregnancy due to the embryonic development is not yet stable, must pay attention to appropriate rest, avoid exertion and strenuous exercise, light diet, prohibit coitus, but also follow the doctor’s advice to continue to take folic acid, in order to prevent the risk of neural tube malformation of the fetus. When there is abdominal pain, vaginal bleeding, etc., you should go to the hospital in time and undergo ultrasonography, blood HCG and progesterone tests to make a clear diagnosis.