Wow...with my 2nd child they told me the same thing. I did however have the amnio (very risky considering I am also RH-). If I had to do it again I would never have it done!!
My little guy came out a little smaller than most but is now a perfectly healthy, happy 8 year old monster!!! I have had no problems other then him being on the short side

!!! Then again I am only 4 foot 9 and daddy is 5 foot 9 so we could be to blame!!! HE HE
In all seriousness if the baby is healthy...let it be ya know. I felt pressured to have the amnio, please don't let them MAKE you do anything!!
What number baby is this for you?? Good luck!1