Sac measuring 1 week behind

[Jilltine]

I had my first u/s at 7 weeks. The baby measured 6 wks 6 days and had a good heartbeat. The nurse told me the sac was measuring 1 week behind. She told me not to be worried, they usually catch up. If it was 2 weeks behind they would be concerned. Of course I am worried. Has anyone heard of this or have any experience with this ?

[SilverAngel679]

About 1 week in either direction with ultra sound is the rule of thumb. A sac measuring 1 week behind shouldn't be too much of a concern.
Just wait and see what happens at your next scan to figure out if you have a real reason for concern or not. good luck with it all and I'm sure your bean wil be just fine.

[kb2131]

hi there,
a word of encouragement. Up until our 9 week ultrasound, our crown rump lengths were always on target but our 1 sac (we are having twins) was 1 week behind. at the 9 week they appeared to be the same size and caught up! our RE and OB advised us that sometimes when you are looking at a 3D object in a 2D setting it can be the way the sac is sitting or it can just simply be the sac is taking a bit longer to catch up. the CRL is more important from what I have learned. good luck to you and we will be thinking of you!

[kholtan]

One of my twins was 5-7 days behind for the first couple months and then the were equal from there out. I wouldn't worry. . . Ok, easier said than done!

Good luck!