^^^^^^what she said^^^^^^^
My wife got diabetes whilst pregnant , was put on metformin and was told if her post meal BGs wherent reigned in she'd be put on injections - this was enough to make her eat right.
The risk to the baby is elevated BGs which will cause the baby to grow excessively (hence why as a diabetic you'll probably be asked to be induced earlier). The best way to minimise this excessive growth is to minimise/ eliminate your carb intake (you'll get plenty of good carbs from things like salads none root veg and if you body really needs it, protein will convert to glucose also).
If eliminating carbs is too extreme, try to heavily restrict them instead (half/quarter your previous portions, stop eating fruit, replace with non root veg, eat more (fat to keep you satisfied etc). Any changes in your eating will affect your BGs so keep regular monitoring up (pre meal and 2hr post)
The other way to reduce your glucose? Medication (as guided by your healthcare provider)... But as many will say, drugs are unpredictable and have side effects.
It may seem tough, but just think, a few months of controlling your eats for a better chance of a healthy easy to deliver baby.