Material and Methods: A prospective study will be carried out. Woman medically diagnosed as high risk for preeclampsia will randomly be assigned to dietary treatment or no dietary treatment groups. In the dietary treatment group, besides medical care, all woman will get calcium and vitamin D supplementation from 8th to 16th gestational weeks, and thereafter until delivery personal extensive nutritional guidance. A 3 day food diary will be collected at inclusion and thereafter at Gestational weeks 16 and 28. All routinely collected data during pregnancy (blood tests, weight, blood pressure and preeclampsia symptoms) will be documented.