The re-occurrence rate isn't a simple formula, unfortunately
and, as it has been said, depends on different factors. One of them being your severity and time of onset (according to my MFM). The earlier the onset, the higher your risk (again according to my doc). Having said that, my doc decreased my risk due to the fact that I am healthy, and have no underlying disorders or risk factors. So, I think it might be best to start out by seeing your OB or even better a MFM for a pre-consultation, so your personal physical status quo and PE history can be evaluated for a re-occurrence rate that applies to you.
MC 3/2009 and 3/2011Henry
(1/1/2010-1/7/2010) - forever loved and missed; severe PE with Hellp; partial placental abruption, classical c-section at 25.6 weeksMatilda
(Nov. 2012, born at 35.4 weeks) - severe PE
Our pain has been put into words, placed into empty cradles, to remember that all our babies lived, that they mattered and always will. - Field of Cradles http://www.fieldofcradles.org/