The way the count it is like this. Start from the first day of your last period, and count back 3 months and add 7 days. There you have it, that is your due date. Hope this helps. Good luck, and congrats!
Your doctor will ask you for the first date of your last period to figure this out. You can also go online and get a pregnancy calculator entering that date and it will give you your approximate due date. Also, you can sign up for free and they will email you weekly with what you can expect during that week of pregnancy. I think its a neat tool. Also, if you are not sure of when your last period started when the doctor does an ultrasound usually around 20 weeks the ultrasound will give you a better due date that the doctor will most likely go buy because ultrasounds are most accurate. Because we all don't ovulate at the same time. Good luck and congrats.
January 11th, 2010. How's that for a brief answer? BTW, congratulations, and let us know.