My sisters were twins, and my mom wasn't able to deliver vaginally because they were in a locked position. One was breech, the other vertex, but essentially the breech's butt was in the way of the other's head, so that neither could progress down the birth canal.
They sure gave her a chance to try the vaginal delivery, though--she was in labor for over 20 hours before the doc made the decision to C-sec. Of course, he was an old-timer (he was in his seventies when my sisters were born, and died six weeks after he delivered them.) The same doc delivered me with basically no interventions (not that there would have been time for 'em anyway, I was quick!)
Say, I was wondering if anyone knew anything about the possibility of vaginal breech waterbirth. I know one of the big risks with breeches is that they'll try to start breathing before their head is out (which is why most docs that will do them do a big episiotomy and use forceps, they want the room to reach in and make an airway and get the baby out QUICK). But they way I understand waterbirths work, the baby doesn't start breathing until exposed to the air, so if their butt is underwater upon delivery, they wouldn't start breathing. (this is presupposing the cord doesn't get pinched, so quick delivery of the head would still be desirable)
breastfeeding, babywearing, homeschooling Heathen parent to my little Wanderer, 7 1/2 , and baby Elf-stone, 3/11!