Hello, my girlfreind is pregnant and is now exactly 20 weeks and 5 Days (as of 29th May 2009). The first time we found out that she was pregnant was on the 23rd Jan 2009 and at that time she was 8 weeks. What was the conception date? I was away from the 17th till the 30th of Dec and the doctors are saying that the conception date was around the 21st - 27th December. Can you please tell me how accurate the conception dates given to me.