Re: US saw only a sac?!
For peace of mind, I would ask to come in for a follow-up u/s in a week or two. I agree that 6ish weeks can often just show a sac so not to worry But 4 weeks seems like a long time to wait for me! Granted, I have a history of losses so my RE was watching me closely, but they had me coming in every 5-7 days so they could closely measure the growth. I'm hoping for a healthy, sticky bean for you!
Erica - Married to Jeff, Momma to Gibson, our rainbow baby Josie, and furbaby Boston Terriers Shelby & Penny, forever missing our angel babies Marshall Feb '11 and our Beans Nov '11 & Feb '12