If you are testing for pregnancy on the day of your period, it is best to do so through a blood HCG test, which is also accurate in this case. Because basically it takes about half a month from the day of fertilization for the fertilized egg to enter the uterine cavity to bed down and secrete blood HCG, so if blood is drawn on the day of menstruation to check the blood HCG, and if the value of the blood HCG is greater than 10 mIU/ml, it indicates pregnancy. It is also recommended to take a blood test on the day of menstruation when it is about 31 or 32 days after menopause to check the blood HCG. If you are using urine test to find out whether you are pregnant or not, it is best to use morning urine test after 35 days of menopause.