This chart is courtesy of the Pregnancy Due Date Calculator on BabyZone.com.

Your Conception Date is:
(Approximately 2 weeks before your next menstrual period)
You’re in your First Trimester (weeks 1-12)
10/31/2007
Your period of greatest risk for birth defects is:  
(5 to 10 weeks gestational age)
11/21/2007
to 12/26/2007
Your baby’s fetal organ formation begins: 11/21/2007
Your baby’s major organs have formed: 12/26/2007
Second Trimester (weeks 12-27)
Your risk of miscarriage decreases:
1/9/2008
If your baby is premature, but born after this date,
s/he has a chance to survive:
3/26/2008
Your Third Trimester begins on:
(27 – 40 weeks)
4/23/2008
Your Pregnancy Due Date is:
(40 weeks – full term)
7/23/2008