Once you go past the due date the placenta starts to breakdown and doesn't work as well which is why they induce you.
I just think 12 days over is too early, particularly when a "normal" pregnancy is anything from 38 to 42 weeks. In any event, we're one of the few countries in Europe which measures gestation at just 40 weeks. In my day, you weren't considered a candidate for induction until you were in week 44.Once you go past the due date the placenta starts to breakdown and doesn't work as well which is why they induce you.