IVF baby measuring a week behind

[Janimal]

I did IVF to get pregnant.  I got a positive HPT at 6 days after a 5 day transfer.

My egg retrieval was 9/18 and my transfer of 2 blasts was 9/24/07, so that's 7 weeks 2 days gestational age as of today.
I had an ultrasound this morning, and the doctor said the baby is measuring at 6 weeks, and the heartbeat is at 104.  He said he was concerned about the baby's measurements.  I asked him how concerned should we bve, he said "very concerned".  
He said all we can do is wait and we'll have another u/s next week to check on the baby's development.

I am freaking out.
I am trying to find any success stories to hand my hat on of babies who measured behind but managed to "catch-up".  Since we did IVF we know the specific dates of conception, so there's no guess work calculating the lmp.

I am so worried --- I'm grateful for any input.

[Zoe2B]

As hard as it is, you need to wait for the week and have another u/s to see how things have progressed. You're still very early. It's out of your hands. I've heard that small babies, and low heartbeats have changed dramatically in one week. There's just no way to know now. Search this forum for old posts that have 'baby's heartbeat' in the subject (I think that's where I saw them) to see if there are any success stories. My prayers are with you. Please let us know how it goes after your u/s.

[1nana]

The fact that the baby is measuring behind and the heart rate is 104 (should be 120-180), I'm sorry to say that it does not sound too promising.