For those who really like to geek out on pregnancy ;-)

diana.filipi

If you want to see some really cool stuff go check out the Carnegie Stages of Embryonic Development.  You'll use the fetal age so on day 1 the egg is fertilized and begins to split.  It does the first 60 days and stops at the end of the embryonic stage.  I like this link: http://embryology.med.unsw.edu.au/wwwhuman/Stages/CStages.htm