In 2009, if you're due on December 4th, I think that means that you conceived on March 17th. But remember that people count two weeks ahead - when you conceived, you were already two weeks along, according to conventional counting.
The week of May 4th
in march
April
1st December
march 21
March 1, perhaps.
around march 21st
The begining of March ( first week)
Roughly Friday December 19th 2008
Roughly Friday December 25th 2009
Based on a normal gestation period of 40 weeks the conception date was December 31st.
December 10th 2010? That would make your conception date roughly March 18th
December 24th give or take a couple of days.