Level 1: The fastest pregnancy test within a week Pregnancy is a matter of great concern to every woman. If you want to know whether you are pregnant as soon as possible, the best way is to take a pregnancy test within a week. This method is the most accurate and can be performed around 6-7 days after fertilization, because at this time the embryo has just implanted and the body has just begun to produce pregnancy hormones. There are many different brands of one-week bags on the market