Hi, My last period started on 11/11/12, so based on that when i made first OBGYN visit on 01/10/13, she said i was 8 and half weeks pregnant. I had my first ultrasound on 01/15/13, and Ultrasound tech told me that on 01/15/13, i was 6 weeks and 5 days pregnant and she will update my chart and system and change my due date to September 05, 2013. I usually have irregular periods, usuall i use to get period during last 4-5 days of the monday between 26-30 of the month last couple of periods started 07/22/12, 08/25/12, 09/30/13 and then 11/11/12. 11/11/12 was my last period before i got pregnant. So now i want to know exactly when i would have conceieved? Is it possible to know this or i should go with the gestational age what ultrasound tech did and determind my due date of 09/05/12. Appreciate your response. Thanks, Viva