On the seventh day after intercourse, a blood test for HCG can be taken to check if you are pregnant, which is the earliest and more scientifically based way to check pregnancy. If the HCG is >5mIU/mL, this is a sign of pregnancy, and the value will continue to increase steadily, doubling every other day, which is a sign of a well-developed gestational sac. If the pregnancy is confirmed on the seventh day after intercourse, the test should be repeated every other day to confirm that the HCG has doubled and then wait until the 45th day of pregnancy for an ultrasound to confirm the intrauterine pregnancy, so that the normal development of the gestational sac can be confirmed. If you want to check with the early pregnancy test, it should be done when your period is delayed for three days, and two bars on the early pregnancy test indicate that you are pregnant.