Pregnancy Timeline Calculation: Estimating Conception Date

Question
I think my last period was on march 1st 2006-but not sure cause My gyn put me on new pills in january and ever since then i was spotting every week so i really am not sure when i got an real period. then in march went back my gyn took me off of those pills and gave me new ones and i was suppose to start them in april but never got an period so from there calculations i am about 9 weeks didnt have ultra sound yet not till next week. So Im trying to figure out when i concieved.

Answer
Unless you know the date of your last period, I can't guess when you conceived. If your last period started on March 1, and you were not on any birth control pills at that time, you would have ovulated around March 14 and could have conceived if you had sex on March 13,14,15, or 16. You would now ber8 weeks 5 days pregnant and wouldf be due on December 8. The sonogram will pinooint it better, since you are really not sure of your last period.