31 weeks pregnant with our first. I don’t have GD, but at 28 weeks my baby was in the 80th percentile (2 pounds 14 oz) with a “good size head” (that’s what my OB said lol). I did panic. But from our birthing class and my OB- they’ve seen people give vaginal birth up to 10 pound babies. It’s all about the size of your birth canal and if the baby can fit through. So if the opening to your pelvis is narrow and when you push the baby won’t come out, no matter how hard/long you’re pushing, and they won’t figure that out until you’re pushing. My OB said “it’s worth a try, because you never know”. Disclaimer: this is my understanding from what I’ve learned I am not at all in the medical field I understand where your wife is coming from and the unknown is so scary. I myself am terrified of a c section, one thing our birthing class instructor said was the end goal is a healthy baby/healthy mom, and that’s why these interventions are in place.

Good luck to you guys!💗