Should be no > wk
If your due date is a firm one, based on good dates &/or confirmed by ultrasound, most ob's will try to induce u if you go much over 1 wk.
The umbilical cord/placenta
begins to wear out & may not supply baby well during a labor
. Teats of fetal well being are often done to monitor this. Have a frank discussion with your OB and get an idea about your unique needs & the options ahead.