Hey, I didn't see this post when I came on yesterday, only just seen it...
I had a growth scan just over 2 weeks ago, I was 36+1, so not as far along as you, and they estimated my LO at 8lb14!!!!! I just went white when they told me! I know there's a margin for error, but the sonographer who was also a midwife said that she was really happy with the angles, did a few different angles and everything and still got the same.
She was even doing a nervous laughter in shock! They said that there are no obvious problems so they won't intervene before my due date, I'm gutted! Have another growth scan on thursday to see if he's got even bigger, which I assume he will after 3 weeks! Then they'll have to see if they think he'll fit through my pelvis!
As for a safe way to make them not grow, I don't think there is one! I've been ill, anaemic, drinking loads of coke (supposedly that gives low birth weight) and still I have a giant!
Best thing is just to think how healthy they are!
xx