Fetus not grown for 2 weeks?

Hope someone can help, my wife had her midwife appt today at 34w and told her measurement has not changed since her 32w check up. We are now really worried, they are sending her for a scan and consultation but its a week away, how can they tell you this and thena make you wait a week. What could happen to my baby if its not growing ? the heartbeat was there and the pregnancy has been fine so far, could the baby come early or could we even lose it or when it comes it have a disability due to this issue? my wife has always been measuring slightly smaller about 1 -2 week out, but the fact they have said its not changed at all, indicates the baby has stopped growing.. we are so scared.. please can anyone help