Cases: women with a history of PE. Control group: women with uncomplicated pregnancies in the history H1: PP interval ½ -2 years: n = 2x 425 H2: PP interval 5-10 years: n = 2x 350 H3: PP interval 10-15 years: n = 2x 282 H4: PP interval 15-30 years: n = 2x 233