I know no one can really answer this question because I wasnt charting. My last period started 9-15 (I have been pretty regular because I was on provera for 4 months). I tested on 10-15 and got a bfn, but it was late in the day. Then tested on 10-20 and got a BFP. The reason I ask is because I have an ultrasound on Monday and I dont know if they will be able to hear the heart beat. I am thinking that if I got a bpn on Oct 15th then I probably ovulated late and maybe not be as far along as I think. I just dont want to be worried about this if they dont hear the heartbeat. What is the earliest you heard it?