After 20 days of intercourse, if the patient conceives, the patient’s pregnancy can be detected. Pregnancy can be detected by the following three methods: first, by checking the blood chorionic gonadotropin, which can determine the patient’s pregnancy more accurately, and by checking the HCG to determine the activity of the gestational sac. Secondly, the urine pregnancy test can determine whether the patient is pregnant or not. The accuracy of the urine pregnancy test is not 100%, so it is recommended to verify the test with morning urine the next day after the test, or to check the blood chorionic gonadotropin for confirmation. Thirdly, ultrasound examination can detect the presence of a gestational sac 20 days after intercourse, and can determine the size of the gestational sac and whether it corresponds to the month of menopause, and can determine whether the pregnancy is intrauterine or extrauterine.