Can someone please help me? My lmp was December 1st 2010 and I am now 9 weeks pregnant according to the ultrasound.. but how do I figure out when I conceived... when I look it up on the calculators online it says I conceived December 30th.. but don't you usually ovulate 14 days after your lmp.. which would mean I conceived on the 15th? My due date is sept 22nd I am so confused..

You won't likely be able to tell when you conceived because not everyone ovulates within the norm. Apparently, according to the ultrasound, you are not as far along as you thought you would be. While ultrasounds are not exact for dating purposes as well, early scans do tend to be more accurate than going with the lmp.

Since you feel the dates may be off, you could ask about having another one done in a few weeks time and see if it remains close to the same. Certainly if your doctor or midwife were concerned about baby's development, and the gestation of the pregnancy, they would do another scan to confirm.

It isn't an exact science.

Unless you've been with multiple partners, a few days one way or the other don't really matter all that much Gestation periods vary from mother to mother, and baby to baby.

Relax. Your baby will be born when it's born. Might be a bit early, might be a bit late.

I'm not a doctor, just a dad.. but trust me on this - when you hold him or her for that first time, you'll forget all about the calendar.