I had my 2nd u/s today at 8w1d. The baby measured 7w5d with hb of 171bpm. I think that's not too bad, but haven't heard from my doctor yet. My main concern is that the gest sac is so small, measuring 6w1d. Anyone have thoughts about that? Some sites say not to worry about sac size if baby is measuring fine, others say if sac isn't 5mm bigger than baby there's 80% chance for miscarriage. Mine is at most 4mm bigger than baby and only half the size it should be according to charts online. Will continue to update as I have more to share, good or bad.