I don't believe that inducing labor is a good idea. There are complications that can occur if labor occurs prematurely. You should consult your veterinarian if there is a good reason for inducing labor.
You should never induce the labor of a cat without the recommendation of a vet. Unless your cat is already in labor but is having trouble getting the kittens out you should let her have the kittens naturally.
You do not want to do this unless the cat is very, very over due and you know this for a face. It is unsafe and if not done by a vet may result in the death of some or all of the litter and likely the mother as well.