We present a case of a 25 year-old female who developed acute hypoxic respiratory failure secondary to postpartum heart failure with preserved ejection fraction. Despite essentially normal tissue Doppler velocities and E/e’ ratio by existing guidelines for the adult population, available literature suggests that our patient’s markers of diastolic function were significantly abnormal relative to what is expected in the third trimester of pregnancy. Advanced echo-Doppler analysis and her clinical presentation support the presence of underlying diastolic dysfunction. This case illustrates the challenges associated with the diagnosis of diastolic dysfunction during pregnancy and the need for pregnancy specific guidelines.