Early Pregnancy Ultrasound: Yolk Sac Visible, No Fetus Seen - What Does It Mean?

Question
I ma 27 had 2 kids,2 m/c's and lmp was Dec 17th.I went for an u/s yesterday and I was 5w 6d.They were able to see the yolk sac and it measured 5w 4d.But they were not able to see the baby.As of Monday(I was 5w 2d) my hcg levels were 12,606.My Dr said it was probably just too early to see the baby but she said it is a possibilty of a blighted ovum. Could I have a blighted ovum with my levels being that good? Or do you think it was just too early also?When can you usually see the baby?They did the u/s that early because I had a tiny bit of brown spotting last week.

Answer
Between 5-6 weeks gestation (from the first day of your last period) we ONLY see an empty gestational sac, but no fetus or fetal heartbeat. After 6 weeks, we usually will see a fetus and a fetal heartbeat. Don't worry. YOur HCG values appear adequate for a viable pregnancy. If, when you repeat the sonogram in a few weeks, there is no fetus, then you have to entertain the possibility of a blighted ovum. At this time, everything appears fine.