Both mine were breech til 32wks, then the bigger twin 2 went head down - and boy did I feel it when he did - lol!!! The leading twin was so squished down at the back of me by "monster boy", that he had no real chance of turning after that. It is possible for babies to turn up until the last minute tho. My friend's twin girls were constantly turning right up until her section at 39wks. They were a normal size for twins, and had more room to manoeuvre x