It might be allowed, depending on the circumstances surrounding the need for the caesarean, but I expect you could meet with some pretty stiff resistance from the hospital. I asked about booking my elective c/s later rather than earlier, given that my first pg went to 42.5 weeks...but they explained if I went into labour before my scheduled date, it then turns into an emergency c/s. Often women go into labour overnight, so there can be a delay in finding surgeons, anaesthetics, theatre space, midwives etc, so the c/s may not be as calm and orderly as it might be scheduled during regular hours.