Prim rose oil! Hands down. Well, are you looking to somewhat help labor along? Prim rose helps open the cervix but ONLY if your body is ready. It is safe and will not put you into full labor if you are not ready but it can really help speed up the process in a healthy manner. Here is information on how to take it:
My midwife recommended it to me :]
http://www.ehow.com/how_4882183_use-primrose-oil-start-labor.html