2 weeks. About 2 weeks later you can detect a pregnancy. Earlier than that and you could have a false test.
How long do I have to wait to take a pregnancy test because I had sex on the day before or on my ovulation day?
1 week after missed. One week after a missed period, a woman can take a urine pregnancy test. There's no need to test earlier, unless she doesn't have regular periods. If she doesn't have regular periods, and therefore doesn't know if she is missing her period, then she can take a urine pregnancy test 3 weeks after having sex. Read more...