The evolution of the diagnostic criteria of preeclampsia-eclampsia

As the understanding of the pathophysiology of preeclampsia has improved, its diagnostic criteria have evolved. The classical triad of hypertension, edema, and proteinuria has become hypertension and organ dysfunction—renal, hepatic, neurologic, hematological, or uteroplacental. However, the most recent definitions have largely been based off consensus and expert opinion, not primary research. In this review, we explore how the criteria have evolved, particularly through the second half of the 20th and the beginning of the 21st century and offer a critical appraisal of the evidence that has led the criteria to where they stand today. Some key themes are the following: the debate between having a simple and convenient blood pressure cutoff vs a blood pressure cutoff that accounts for influencing factors such as age and weight; whether a uniform blood pressure threshold, a rise in blood pressure, or a combination is most discriminatory; whether existing evidence supports blood pressure and proteinuria thresholds in diagnosing preeclampsia; and whether using flow-charts and decision trees might be more appropriate than a single set of criteria. We also discuss the future of a preeclampsia diagnosis. We challenge the move toward a broad (vs restrictive) diagnosis, arguing instead for criteria that directly relate to the prognosis of preeclampsia and the response to treatments.