Understanding Due Date Discrepancies: LMP vs. Ultrasound

Question
Hey.. My first day of LMP was on 8th Feb. So my due date as per LMP calculation should be 14th Nov 2008. However, my ultrasound has predicted 3rd DEC 2008. I knew it may differ. But in my case, difference is 3 week which is confusing me. Do you think this is normal

Answer
Yes, this is normal. Ultrasounds are only estimates. They usually are plus or minus a week. If you or your husband are smaller boned people, your baby will likely be on the smaller side as well. Also it's possible that you don't ovulate until late in your cycle, like on day 14. Good luck. I hope this helps.
Suzette