Many women are eager to know if they are pregnant after having sex, so when is the most accurate time to test for pregnancy? Generally, the morning urine test with a morning pregnancy test paper 7-10 days after menstruation is over the cycle will be able to test accurately. If a blood test is taken for HCG, it can be accurately tested 10 to 12 days after intercourse. A woman’s pregnancy is determined by testing the level of HCG in her urine, which is also known as chorionic gonadotropin, a hormone that is normally found in women’s bodies but at very low levels. However, after pregnancy, due to the stimulation of progesterone and estrogen, HCG levels increase dramatically and are reflected in both urine and blood. Therefore, we can determine if we are pregnant by testing HCG in urine and blood. HCG is produced when the egg and sperm unite and the concentration increases with time. The concentration in the blood is usually detectable about 10 days after the fertilized egg is produced. The concentration produced in urine takes longer and can be tested only after a week or so of menstruation beyond the cycle. If the blood HCG level is high, then an ultrasound examination of the uterine appendages is needed in conjunction with the ultrasound to determine a normal intrauterine pregnancy, as ectopic pregnancies can also have high HCG levels, so an ultrasound examination is necessary to identify them.