Even if pregnancy occurs 7 days after sexual intercourse, the level of human chorionic gonadotropin (HCG) in the body is still relatively low, and pregnancy tests usually cannot detect pregnancy. Pregnancy tests measure the level of human chorionic gonadotropin (HCG) in the urine. Seven days after sex, if fertilization of the egg has not occurred, the test will not detect pregnancy. Even if fertilization is successful, HCG levels in the urine are low at this time, and are usually not detectable until about 10-15 days after sexual intercourse. And the test paper test is prone to improper measurement methods, test paper quality problems and other factors, so the test results are not completely accurate. It is recommended that if you notice symptoms of pregnancy, such as delayed menstruation, breast tenderness, etc., you should go to the hospital in time, and under the guidance of the doctor, have your blood human chorionic gonadotropin measured in order to determine whether or not pregnancy is occurring.