Preeclampsia, the leading cause of death in pregnant women, is a medical mystery and a disorder that every obstetrician dreads. Without warning, the blood pressure of a seemingly healthy pregnant woman may surge; if the baby isn't delivered right away, she may die. Preeclampsia kills an estimated 76,000 women worldwide each year, but no one knows its cause or how to prevent it. Now, a new study this week in Science Translational Medicine demonstrates that—like Alzheimer's, Parkinson's, and mad cow diseases—preeclampsia is distinguished by misfolded and clumped proteins. The finding offers an entirely new take on this complication of pregnancy, and pinpoints a potential biomarker, so that a simple urine analysis could definitively diagnose a disorder that has lacked a gold standard test.