hCG levels in weeks from LMP (gestational age)* :
3 weeks LMP: 5 - 50 mIU/ml
4 weeks LMP: 5 - 426 mIU/ml
5 weeks LMP: 18 - 7,340 mIU/ml
6 weeks LMP: 1,080 - 56,500 mIU/ml
7 - 8 weeks LMP: 7,650 - 229,000 mIU/ml
9 - 12 weeks LMP: 25,700 - 288,000 mIU/ml
13 - 16 weeks LMP: 13,300 - 254,000 mIU/ml
17 - 24 weeks LMP: 4,060 - 165,400 mIU/ml
25 - 40 weeks LMP: 3,640 - 117,000 mIU/ml
Non-pregnant females: <5.0 mIU/ml
Postmenopausal: <9.5 mIU/ml
When I had a scan at the ER at about 5 weeks all I saw was a gestational sac and yolk sac. By my at 8 week u/s we could see it all, with a very strong hb!
Your HCG is on track and so is what you saw! Stay positive, because all is well!!!!!!
HCG can vary so much person to person and pregnancy to pregnancy. But they do say that you can't see much by ultrasound until the HCG is over 1000-2000. At 5 weeks it is very common to see just the sac and nothing else. Around 6/7 weeks they should see the fetal pole, and a heartbeat the 8th week. If everything measured correctly for 5 weeks then I think you are in great shape. Happy pregnancy!