My son had iugr and measured small throughout my pregnancy. They did discuss bringing his delivery forward when his hc and ac remained static. The extra monitoring I had was extra scans, ctg and blood flow doppler across the placenta every few days.
I wasn't going to be allowed to go passed 36 weeks, but my son was severely growth restricted. He was fine when he was born, just small.
If his growth had continued along his own curve and they were happy with amniotic fluid levels and blood flow across the placenta then they would have left him a little longer, but as his growth had stopped they decided he was better off out.