Hypertension during pregnancy remains a common and potentially devastating complication.1,2 Hypertension can be isolated (gestational hypertension) or associated with proteinuria (preeclampsia) and, rarely, can manifest as a consequence of either preexisting or new onset renal (usually glomerular) disease. Preeclampsia is a particularly worrisome diagnosis, because it carries increased risk for morbidity to the mother and child and may accelerate to the condition of eclampsia in which seizures develop in association with a high risk for fetal and maternal mortality. Although, ideally, the diagnosis of these conditions should involve the use of biomarkers that reflect the underlying pathophysiology of the disease process, the lack of clinically available assays has forced the clinician to diagnose the condition based solely on the clinical presentation. Unfortunately, although establishing cut points for elevated blood pressure and urine protein excretion appears to be straightforward, these continuous variables lend themselves to arbitrary definitions, and this likely explains why the precise definition of preeclampsia has changed several times and why different organizations continue to classify preeclampsia differently.3 A recent report from the National High Blood Pressure Education Program Working Group on High Blood Pressure in Pregnancy3 nicely summarized the current status of diagnosing preeclampsia: “Although our current understanding of this syndrome has increased, the criteria used to identify the disorder remain subject to confusion and controversy. The confusion doubtless reflects the fact that preeclampsia is a syndrome, which means that attempts at definition use arbitrarily selected markers rather than changes of pathophysiologic importance.” Adding to this confusion is the fact that a …