i'm not sure if it is POLICY but the royal womens hospital in brisbane induce between 41+3 and 42 weeks. i didnt realise they let you go til 42 weeks when i had my DD and they induced me at 41+3, i would have waited longer if i had known. so i PRESUME they like to get it done earlier rather than later.

i think the risk is that the placenta and umbilical cord start to degenerate if left for a prolonged time frame... having said that though they can do ultra sound to check on its functioning.