Introduction to ISSHP new classification of preeclampsia

The classification of the hypertensive disorders of pregnancy has always been a crucial point, especially in the scientific literature, to compare results from different series. Some of the classes have been reviewed during time, and some new ones have been added, paralleling the increased knowledge of the diseases and syndromes. Among the interests of a society there is the sharing of a common language and the guidance to give to scientific authors and editors for better presentation of their results and outcomes. Still leaving unchanged the definition of the five major classes of the hypertensive disorders of pregnancy (gestational hypertension, preeclampsia, chronic hypertension, preeclampsia superimposed on chronic hypertension, eclampsia) we realized that in the last years emerged a need to better define some forms of preeclampsia, especially in terms of severity and time of onset and indicated delivery. This is why the International Committee of the International Society for the Study of Hypertension in Pregnancy (ISSHP) was requested to come to a consensus, by responding to a questionnaire, on the thresholds to define "severe preeclampsia", and "early onset preeclampsia", and on which parameters to use to define the HELLP Syndrome and which other definitions may be added. There was an agreement to define "severe preeclampsia" by blood pressure values >160mmHg systolic or 110mmHg diastolic. The amount of proteinuria was considered not useful to define the severity. The HELLP syndrome was considered a feature to include in the severe classification, and that could be identified by a reduction of platelet count below <100,000/dl, an elevation of ALT or AST twofold the upper limit of normal, and an elevated LDH (twofold the upper reference limit or greater than 650IU/l). There was an agreement to define "early-onset preeclampsia" as that occurring before 34 weeks. The results of this survey can help in updating the previous ISSHP classification.