A pregnancy test can detect pregnancy as early as 10 to 14 days after conception, which typically corresponds to around the time of a missed period. This is when the hormone human chorionic gonadotropin (hCG) starts to be produced by the placenta after the fertilized egg implants in the uterus. Highly sensitive home pregnancy tests can detect hCG levels low enough to indicate pregnancy a few days before the missed period, with some tests detecting pregnancy up to 6 days before the missed period (about 5 days before the expected period). Blood tests for pregnancy are even more sensitive and can detect pregnancy within 7 to 10 days after conception. For the most reliable results, it is generally recommended to take a pregnancy test on the day of or after the missed period.