If you are trying to determine whether you are pregnant or not, you can use a pregnancy test as early as one week after intercourse on the day of ovulation; because it takes at least one week for the sperm and egg to combine to form a fertilized egg and to settle in the uterine cavity. The day of ovulation is the day when a mature follicle is discharged, and the chances of getting pregnant are higher on that day; the sperm and egg combine to form a fertilized egg, which develops while moving towards the uterine cavity and takes at least a week to develop, so the earliest you can test yourself with pregnancy tests is a week later. The chances of pregnancy are higher when you have intercourse on the day of ovulation, but it does not mean that you will definitely get pregnant; in addition, due to the different conditions of the fertilized egg’s development and implantation, the negative test result after one week does not mean that you are definitely not pregnant; it is best to take an early pregnancy test after two weeks of intercourse for a more accurate result. If the tested person does not understand what the test result represents, it is recommended to consult a professional obstetrician and gynecologist.