A mother in labor came in from health center as a referral to the hospital I was training at, with arm prolapse fetal demise. We hurriedly prepared this mother for an emergency Cesarean delivery. She was fully dilated as we did all this and our fear was that as she pushed with each contraction, she would rapture her uterus or get symphiseal diastasis due to the very large presenting diameters. To our surprise, she managed to push the baby out. The baby most of the ribs and the clavicles allowing it to pass through the birth canal.
I think it also depends on the actual event as it is at the time. If early in labor, or not in labor at all, then Internal podalic version can be attempted by an experienced obstetrician. Alternatively, surgery could be done to deliver the baby. In unique cases, like the one I had, then the baby is delivered vaginally.
This is a very difficult Obstetrical scenario and you can rarely manage it without some sort of complications. If at full dilatation with prolonged rupture of membranes the uterus will be clamping on the baby with not much space due to the lack of amniotic fluid and will make it very challenging to perform internal podalic version. Although it is sad to have to perform a C/S for a dead baby but may be the only technically possible and safe way to deliver the baby. However, you will need to be prepared for a very difficult caesarean with anticipated massive post partum haemorrhage.