I don't know why some women are more at risk. Hopefully in time research will provide answers and preventative measures. I have read a list of steps to take to avoid future Prem.Rupture of Membranes, and you would practically have to stay in bed for most of the pregnancy.

The medical advances for saving prems have been amazing - I read something like 30 years ago only around 5% of 27 weeker prems survived, but now at least 95% survive.