I need to know how long I should wait to test for pregnancy if I think I concived right before my menstral cycle is supposed to occur. I am about 2 days late but I don't know how long it takes for the hormone that says I'm pregnant to show.

Normally, conception occurs in the middle of the menstral cycle, and you get a reliable reading on a home test about two weeks later, or around the time your period was due.

While it's not impossible, it's unlikely that you got pregnant right before your period. If your period doesn't show, and you know this was the only time you had sex, then two weeks should be long enough to wait to test.

Unless you ovulate late your chances of becoming pregnant right before your period are slim and a pregnancy test wouldn't show it yet. You need to wait 7-14 days after you believe you conceived and hope it shows up if you are. I had to wait a week or so after my period was due for both of mine to show up the first one took 3 weeks to show and I lost it due to miscarriage.