The diagnosis of peripartum cardiomyopathy is one of exclusion, made after careful search for an underlying cause. Research in this area is compromised by the reliance of some on clinical criteria alone without strict echocardiographic criteria. This article argues for uniform criteria that define peripartum cardiomyopathy, similar to the criteria for idiopathic dilated cardiomyopathy set forth by a National Heart, Lung, and Blood Institute-sponsored workshop and proposes that the new definition include heart failure within the last month of pregnancy or 5 months postpartum; absence of preexisting heart disease; no determinable etiology, the traditional definition; and strict echocardiographic criteria of left ventricular dysfunction: ejection fraction less than 45%, or M-mode fractional shortening less than 30%, or both, and end-diastolic dimension more than 2.7 cm/m2. Mortality from peripartum cardiomyopathy remains high, 25-50%, and a recent review related long-term prognosis to echocardiographic measures of left ventricular chamber dimension and function at diagnosis and recovery. We describe a modified pharmacologic echocardiographic stress test that might be useful in determining left ventricular contractile reserve in women believed to be recovered by routine echocardiographic studies. The test reproduces hemodynamic stress akin to pregnancy, and the data might be useful when counseling women on future childbearing. Women who respond with reduced cardiac reserve might be advised to avoid pregnancy.