Growth sono?

I'm just wondering when my next growth sono will be? I had one at 27 weeks and he was just about 3 lbs. (measuring almost 3 weeks bigger) I am going for my 31 week appt. tomorrow. I didn't know if they were going to do it at 33 or 35 weeks? The baby will be born no later than 39 weeks by c-section. Any ideas? Thanks!

Message edited 7/18/2006 4:07:50 PM.