Diabetes and a small baby?

Felicia
I'm currently 34w3d and was disagnosed with Gestational Diabetes at 30 weeks. Every time I've seen the high risk doctor he's always commenting on how small my baby is and told me today that the baby must be genetically small (he weighed 4.8 lbs). Judging by the measurements on the ultrasound today he was measuring as small as 31 weeks on some of them and the doctor didn't seem concerned at all when he told me before that something could be wrong with my placenta. Has anyone else ever had GD and still had a small baby?