Sometimes in the begining the baby can measure 1 week ahead or 1 week behind. When I had my 8 week ultrasound it said I was about a week further along then I am, I just go by the dates that I know.
U/S measurement for due date vs. LMP
August 01, 2008
So here is my question. I do not have a regular 28 day cycle and I know that when I got pregnanct I did not ovulate till aroudn CD 20. I tried to explain this to my OB but they didn't take that in consideration - still tracked it in the u/s machine - LMP as 5/17. Well the baby measured crown to rump 10w3days but when she put in my LMP at 5/17 she said I am now 10w6days. I am confused b/c there is no way that I am that far along. She said that number was the mix between measurement and LMP. Since my cycle was not 28 days would it be more accurate to awesome I am 10w3day b/c of the measurements?
The CRL is the most accurate. You would be at 10w3days. Same thing happened to me and the U/S tech said she would put in my LMP for the due date and that scared the heck outta me coz I was a week behind and the heart rate was super low for a dating based on LMP. But I had another U/S 2 weeks later and after confirming the dates with the 1st U/S they put a due date based on my 1st U/S and 2nd U/s and they were the same
Actually speaking, the U/S taken in the 1st few weeks of pregnancy will only give you the right due date. In the 2nd and 3rd Tri, they arrive at a date based on the growth of various parts of the body, like femur, heart, lungs, stomach etc and each of them would be different. Like, the heart would be 20 W, the stomach could be 21, the brain could be 2 W 4 D etc. So, the 1st tri U/S measurements are the most accurate to determine due dates.
August 01, 2008