You can measure early pregnancy before you get your period, but because the pregnancy time is relatively short, it may show a weak positive, this result does not determine the pregnancy, you need to wait a few days to test again.
Under normal circumstances, it takes more than 11 days between intercourse during ovulation to detect pregnancy. If a woman is in a hurry, she can consider going to the hospital to take a blood test, and if the HCG in the blood is elevated, the likelihood of pregnancy is relatively high.
If the menstrual cycle is relatively stable, 10 days after intercourse with a pregnancy test, you can also detect pregnancy, and there is not much correlation with the pre-menstrual and post-menstrual period, because some people may have delayed menstruation.
When using pregnancy test paper, you need to go to the morning urine test, morning urine will be more concentrated, the test results will be more accurate.