You can not say with sure that pregnancy will take place even sperm reaches the egg. Pregnancy occurs when sperm combines with egg. This combination is called fertilization. After this fertilized egg travels down towards uterus and reaches there in 7-10 days. This is called implantation. So, after 7-10 days of implantation, there are chances that your pregnancy test will become positive. But it will be good to get pregnancy test on missing of periods on due dates.