It is recommended to use morning urine when testing for pregnancy. Morning urine is tested around 10 days after the menstrual period is delayed, which is the most accurate and effective time with the lowest probability of false negatives. Pregnancy tests are mainly done using early pregnancy test strips or pregnancy test sticks to detect the concentration of HCG in the urine. The concentration of HCG in the urine is affected by the concentration of HCG in the blood, and also by the dilution of the urine inside the urine, so if the urine is diluted due to drinking too much water during the day, a false negative may also occur. When the concentration of HCG in the blood is low, it cannot be reflected by the HCG in the urine, and the concentration in the urine is too low, which can also lead to false negatives. HCG testing by blood draw is relatively the most accurate, and the increase in HCG can only be drawn from the mother’s blood on the eighth day after the formation of the fertilized egg. To detect HCG elevation through urine, it is recommended to take a urine test around 10 days after the menstrual period is delayed.