Early Pregnancy Concerns: hCG Levels vs. Ultrasound Findings

Question
Hi my name is Janis im 25.Because of my LMP march 17th 2006 i should be over 7 weeks pregnant.Last week thinking i was 6.2 weeks i went for an ultrasound.The tech said i was measuring 5.1 weeks and saw no baby.The thing is my levels that day were 16138 ,and not seeing a baby with those levels must be a bad sign?.Im never wrong about my period so im thinking i ovulated later, but the thing that confuses me is... I have high levels for 5.1 weeks last tuesday and no sign of a baby.Today because of the ultrasound stating my baby is 5.1 weeks i should be about 6.1 weeks.Im wondering my chances of seeing a baby this week on a vaginal ultrasound?.I heard having levels of 8000 you should be able to see the fetal pole and yolk sack ,but in my case(doubled that) we saw nothing..*possible yolk sack though* ,but the tech was not sure because my dates were off a week...I guess i need reasurance.




Btw... Are you related to a Rappaport in the montreal jewish general hospital?.Rare name so im curious.He is my ear doctor.

Answer
When a sonogram is taken at less  than 6 weeks, we usually only see an empty gestational sac but no baby or heartbeat. However, if your period started on March 17, by now you should be 8 weeks, esoecially with an HCG value of over 16,000. I would get two blood tests for pregnancy, 48 hours apart . If there is a a doubling  of the reseults in 48 hours, and you still do not see a baby in  the uterus, you have to consider the possibility of a tubal pregnancy.