Only fresh Pineapple helps start labor canned doesn't do a thing. But like anything else it works for some women and not others so if you like pineapple give it a try. :)
It really put me into labor. I was 40 weeks and 0 progression of cervix on my due date, I went home and ate a TON of pineapple...I mean a ton, and I was in full labor by that night. It's nothing going to cause preterm labor or anything, and if your body isn't ready for labor it won't do anything.