I used cauliphium (spelling may be a little out ). It is a homeopathic. It is said to aid the dilation of the cervix and an easier childbirth. It is used from about 35 weeks onward. I used it with all of my pregnancies (except the first). Many women use it when wanting a VBAC - with great effect.
You would need to consult a homeopath but it is truly worth it in my opinion...