How many days after conception can you use a test strip to detect pregnancy? Pregnancy is one of the things many women want most. When a woman becomes pregnant, she needs to confirm whether she is pregnant. So, how many days after conception can you use a test strip to detect pregnancy? The following is the relevant analysis: 1. How many days after conception can pregnancy be detected? Generally speaking, signs of pregnancy will appear 8-10 days after a woman ovulates.