I had GD with my DS, couldn't control it with diet but did control it with insulin. He was born 8 pound, so pretty average. TBH, if the sugar levels are controlled then I don't see why the baby would grow any bigger than any other pregnancy. The data for GD is taken from Type 1 pregnancy outcomes, which is flawed because T1 pregnancies are often subject to high sugar in the first tri and throughout the entire pregnancy rather than the few weeks at the end like GD, as well as BSL's in T1 mothers being much harder to control so are likely to be much higher than GD.

Anyway, long story short - yep, it is possible to have a normal sized baby when dealing with well controlled GD.

Good luck xx