The definition of severe and early-onset preeclampsia. Statements from the International Society for the Study of Hypertension in Pregnancy (ISSHP)

Objective: There is discrepancy in the literature on the definitions of severe and early-onset pre-eclampsia. We aimed to determine those definitions for clinical purposes and to introduce them in the classification of the hypertensive disorders of pregnancy for publication purposes.

Methods: We circulated a questionnaire to the International Committee of the International Society for the Study of Hypertension in Pregnancy focusing on the thresholds for defining severe preeclampsia and the gestation at which to define early-onset preeclampsia, and on the definition and inclusion of the HELLP syndrome or other clinical features in severe preeclampsia. The questions were closed, but all answers had space for more open detailed comments.

Results: There was a general agreement to define preeclampsia as severe if blood pressure was >160mmHg systolic or 110mmHg diastolic. There was scarce agreement on the amount of proteinuria to define severity. The HELLP syndrome was considered a feature to include in the severe classification. Most investigators considered early-onset preeclampsia as that occurring before 34weeks.

Conclusions: A definition of pre-eclampsia is paramount for driving good clinical practice. Classifications on the other hand are useful to enable international comparisons of clinical data and outcomes. We used the results of this survey to update our previous classification for the purposes of providing clinical research definitions of severe and early onset pre-eclampsia that will hopefully be accepted in the international literature.