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Ultra Sounds And Accuracy

2 posts on this thread and the last post was on May 17th, 2008 11:12 PM
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sully92 - May 16th, 2008 3:38 PM
 [Original Post]

I was away at job training from Jan 10th to Mar 8th. My girlfriend was not feeling well and having symptoms consistent with pregnancy. She took a home test at the end of Mar, results were neg. Her symptoms continued, so she took another one at the end of April, results were pos. We had our first u/s May 16th and were told she was 11 wks and one day. Obviously my concern now is that would put conception around Feb 27th, 28th, and thats more than a week before I was home. Is it possible for the u/s to have this much of a margin of error? I know its possible, but how likely is it that the u/s is this far off?

AMB - May 17th, 2008 2:34 PM

umm...I am a sonographer and when using my pregnancy wheel (and double checked from a pregnancy calulator)... it said that if you were 11 weeks on May 16 that probable date of conception would be around March 15. ........................one thing that one must remember when calculating a due date.....We start our calculations based on LMP...and that is two weeks before you actually are pregnant...........does this make sense? so basically the Feb 27, 28 range should have been the dates of LMP not conception.....so the ultrasound isn't wrong....it is actually pretty much on track.


Teddyfinch - May 17th, 2008 11:12 PM

yeah the week age our ob's give us are based on our first day of our last period. for example: i know i conceived on the 1st or 2nd of march (trigger shot) but i'm 13w5d now based on feb 11th being the first day of my last period. its confusing but sounds right to me.