As a disclaimer, I'm not sure this post has much to do with diabetes, either.
One thing we learned at our 36-week labor scare was that baby was lying posterior. This means that if I were lying on my back and he came out, he would be looking up (towards the ceiling) upon emergence, rather than down (towards the floor). I heard one funny story from a friend whose husband almost passed out when he saw her third baby emerge posterior. I had heard scary stories about posterior babies getting stuck, and labor hurting a whole lot, mostly in the back. I had been told by my doctor that sometimes baby turns right before labor begins, and sometimes baby twists during labor. I had heard about the Rebozo technique, using a special blanket and two labor companions to encourage baby to turn. I had heard about inversions for getting a baby to turn, but I had also heard this could cause cord prolapse, where the umbilical cord slips between the baby's head and the cervix and gets compressed during contractions, cutting off blood supply to the baby.
To correct baby's position, to put him in the ideal "LOA," or left occiput anterior, I spent a lot of time on hands and knees, doing pelvic tilts, in the hope that the tilting would dislodge his head just enough and the weight of baby's back would pull down just enough to twist him around. But alas, 3 weeks and almost an hour spent on hands and knees every day and he would always return to the same position. I became familiar with how it felt when he was partially rotated, with his back to one side, and when he was firmly posterior, with his spine lined up almost exactly with mine.
I did have back labor, but the good news is that he seemed to turn enough to come out. I don't know how or whether this would have been different if he had been my first, not my fourth. I don't know whether his size had anything to do with it, but he wasn't that much bigger than any of the others. I don't think diabetes had anything to do with it, but I'm sure that someone can come up with a crazy hypothesis that explains why the two are related. I still have no idea why or how it happened, given that I did nothing different this pregnancy than any other.
One interesting note I will make is that I still have pain way down low, in my sacral area, on my back. I feel certain this is related to the baby's position and possibly the stress of labor. I'm hoping that it resolves as I continue to recover. Going to see a chiropractor is something I've heard wonderful things about, and may consider if it doesn't improve.