University of Liege in Liege, Belgium have discovered miR-146a a new molecule that can serve as a potential biomarker for peripartum cardiomyopathy. Peripartum cardiomyopathy (PPCM) is a deterioration in cardiac function that occurs in pregnant women during the last month or in the months following their pregnancy. Struman and colleagues found that expression of miR-146a was induced by the nursing hormone prolactin. MiR-146a expression promoted vascular damage and was increased in a mouse model of PPCM. Conversely, loss of miR-146a in mice prevented PPCM. Importantly, miR-146a expression was elevated in the serum of pregnant women who developed PPCM, suggesting that serum miR-146a levels could predict which patients are at risk for the disease. In a companion commentary, Richard Kitsis of Albert Einstein College of Medicine in New York, discusses the potential implications of this work for the identification and treatment of PPCM.