Baby measuring on 90th centile at 30 weeks..

Hi guys, so firstly had a midwife appoibtment this morning who done the measuring by tape over top to bottom of belly.. she said it came back that baby was looking small measuring at 28 weeks when im 30 weeks.. she sent me for a scan and see a consultant.. had scan earlier today, and measured baby who then the ultrasound lady said was measuring big!! She was on the 90th centile rather than the other way round!!! Went and saw the consultant who said that he wanted to check for diabetes.. has anyone had this before? Or not had diabetes and baby growing big?! Not too sure how this is looking to go as really hope not to have a section!!