With a 31-day menstrual cycle, you can go to the hospital 10 days after intercourse for a blood test to check if you are pregnant, or you can use a morning-after pregnancy test 16 days after intercourse to detect pregnancy. Generally, you can tell if you are pregnant by taking a blood test for HCG (human chorionic gonadotropin) levels 10 days after intercourse. While early pregnancy test paper detects the HCG level in urine, which is often lower than that in blood, so it is usually possible to detect pregnancy with early pregnancy test paper 16 days after intercourse, and it is best to use morning urine in the test. Women need to go to the hospital for an ultrasound examination about 45 days after menopause to observe whether there is a pregnancy sac present and to determine the development of the fetus and the location of the pregnancy. Women who are preparing for pregnancy should maintain good living habits and mentality, and take folic acid before and after pregnancy as prescribed by the doctor.