Infants that are born to mom that are obese tend to have more complications around the time of delivery secondary to diabetes. Infants of diabetic moms can be too large. They can be hurt at the time of delivery. They might have low blood sugar or their organs may not be mature. They may be more like a preemie despite being full-term.
Those are complications that are mostly related to gestational diabetes. However, there's also the effect of the increase body fat on the newborn that's going to affect that baby throughout the rest of their life. That child is going to be more likely to have complications such as type 2 diabetes and the metabolic disorder.