In less than a month, sometimes pregnancy can be detected. If the menstrual cycle is usually short and ovulation is relatively early, then conception is usually relatively early after intercourse and can be determined by a blood HCG test more than 10-15 days after intercourse. However, if you usually have a long menstrual cycle and conception is late, generally most of the time, you need to wait for more than one week after menstruation stops to detect whether you are pregnant. Therefore, each person’s menstrual cycle time is different and conception is early or late, then the time to detect it is also different. You can consider a blood HCG test for an initial test at the earliest ten days or more after intercourse. If you use early pregnancy test paper or pregnancy test, you can consider taking a preliminary test more than 15 days after intercourse to determine if you are pregnant. The above content is for reference only. Please refer to the doctor’s instructions for specific medication and treatment.