While pregnant, I participated in a study about C and E to prevent PROM, because as a smoker I was at slightly higher risk. I think it was 2 pills each, each day, for the last 4 weeks of pregnancy.
First, the study was safe, because a previous study had proven that large doses of C & E don't harm mom or baby. So, there's no risk involved in trying.
Of the women in the study, there were no PROM, and not one woman began labor with her water breaking. There were double the amount of babies born in the caul, and one even born in a still complete sac. There were half as many respiratory infections, conjunctivitis, or meconium stained waters.
My water didn't break till I started pushing. And the membrane was the thickest and toughest I've ever seen- the midwife showed me how she could barely pierce it with her fingernail.
I'm convinced, it really works.