Fetal Growth Discrepancy: Ultrasound Measurement Concerns - Pregnancy Forum

Question
Hi, I am 14 wks/ 4 days pregnant. My last cycle was Thursday August 5, 2010 and am positive of that. I just had an ultrasound today and again was measuring a big baby at 14 wks/ 4 days when actually by my last menstrual cycle should be 13 wks/ 4 days (today, on November 8). I had an early ultrasound at 5 weeks (Sept. 11) measuring 5 wks/ 4 days, when I thought I was just starting my 5th week. I then had another one at 7 weeks (sept 21st) measuring 7 wks/ 1 day. So today on November 8th, when measuring 14 wks/ 4 days, it seems they are now adding an additional few days ahead. The only time this month that I could have conceived was August 15th. Based on that it seems these measurements would be correct but I'm not sure and wanted another opinion, if you would be able to tell me what you think the possible conceived date is since they say I am measuring a week or so ahead. Is this a big difference? They said they would keep my due date as being May 12, 2011 still. Thanks for your opinion!

Answer
Dear Laura,

I am so sorry it took awhile to get back to you.  Based on what you have told me, they would not change your due date in the first trimester unless the ultrasound shows a discrepancy of 5 days.  This is the case with most, not all doctors.   Also to keep in mind measurements taken are operator dependent, so based on the person doing the scan you could be a little off on the due date.  It does seem that the measurements are correct from when you conceived.  But not a big enough difference to change your due date.  

Take care!
Sara