Quoting preggomyeggo21:" I mean, is it really possible to conceive that late in a cycle? To skip a period and then get pregnant AFTER? 3 weeks behind is a lot."
w my first pregnancy, i had had sugery, and me and dh only had sex once that month...3 days before my period was due, so i know for a fact, that was when he was conceived. i have 26 day cycles, and by no means is 3 days bfore af ideal o time, so very possible! if they didnt say anything, i wouldnt worry. i was very concerned and was asking a lot of questions about the differnce in due date and lmp this pregnancy, and they said not to worry. so im sure its nothing! good luck!