In general, women can be detected 18 days after intercourse or 8-10 days after their menstruation has been pushed back, and the time varies slightly with different methods of early pregnancy detection. Specific: 1, early pregnancy test paper detection: about two weeks after pregnancy can be detected using a pregnancy test stick, using a pregnancy test stick is mainly to detect the concentration of chorionic gonadotropin in the urine, if the time is too early, there will often be false negatives. If you have regular menstruation and your period is overdue for more than three days, most of them can be detected by using a pregnancy test; 2.Blood test: blood test is the earliest way to know the result of pregnancy, you can go for blood chorionic gonadotropin test 10 days after sex; 3.B ultrasound: ultrasound can find out about 40 days of pregnancy, because the pregnancy sac can enter the uterine cavity only about 40 days after pregnancy. Ectopic pregnancy can be ruled out, it is recommended to go to a regular hospital for examination, which is safer; 4, temperature detection: women can measure their body temperature every morning after waking up, generally the body temperature is below 36.5℃ before ovulation, after ovulation the body temperature will rise 0.3℃-0.5℃ and hold for 12-16 days, averaging up to 14 days, the high temperature curve of the basal body temperature can be diagnosed as pregnancy if it exceeds 18 days.