Baby measures 2 weeks bigger than gestational age

[mlh331]

At my 20 week ultrasound, the baby was measuring a full 2 weeks bigger!  I know what day my last period started.  No doubt. The period I had seemed normal to me; typical period for me.  It started 28 days after the previous one began.  Can you say text book? According the the 2 week theory, I would have had to get pregnant the day (+/-) I started my period.  Is it possible that I could have gotten pregnant the month before, but still had a normal period?  My husband and I (thinking that I wasn't pregnant) began trying again two days after my period end and then through out the month. I doubt that I could have gotten pregnant two days after, that would be only 7 days from LMP to ovulation!!!  But it still wouldn't explain 2 week difference (but would explain a 1 week difference).

This is my third child.  My two previous pregnancies measured exact for their gestational age.  They were both "conceived" mid cycle. Both of my children were 7.5 pounds at birth and were both born within 48 hours of their EDD.  I'm really perplexed as to what is going on here! Any insight would be greatly appreciated!!!!!!!

[chellybeans]

did you have an early ultrasound too? ultrasounds can be off a week or so in either direction and earlier ultrasounds are more accurate.

[mlh331]

No, I only had the one done at 20 weeks.  A week off wouldn't make me question.  It's 2 weeks off that has me confused.

[jen2006]

Get ready for a big baby :)  My smallest one was 8 lbs :)

[Dianislee]

I AM HAVING THE SAME ISSUE... IM WORRIED AND I DONT KNOW IF I SHOULD BE. IM PRETTY SURE ABOUT MY LMP AND ACCORDING TO THAT I AM 18 WEEKS BUT IN THE ULTRASOUND IM 20 WEEKS...WHAT THE HECK DOES THAT MEAN???