Although influenza virus is a rare but recognized cause of myocarditis and pregnancy is a known risk factor for the development of peri-partum cardiomyopathy, the association of H 1 N 1-associated severe viral pneumonia combined with features of troponin negative myocarditis and cardiomyopathy in our two consecutive patients raises the novel and hitherto unreported association between H 1 N 1 infection and myocardial involvement which increases the risk significantly for pregnant women. The absence of an acute rise in cardiac enzymes and the low sensitivity of transthoracic echocardiography in recognizing myocarditis may be detrimental to early recognition and institution of appropriate treatment as may be seen in up to two out of three patients. Obstetric providers need to be prepared to provide the care necessary to address the increased morbidity, mortality, and pregnancy-related complications (including spontaneous miscarriage and pre-term birth) faced by pregnant women during an influenza pandemic [21] . Many obstetric health care workers often lack knowledge regarding the safety and importance of influenza vaccination during pregnancy. Misinformed or inadequately informed health care workers may represent a barrier to influenza vaccine coverage of pregnant women. This lack of knowledge among the health care workforce takes on added importance in the setting of the H 1 N 1 2009 swine-origin influenza pandemic [22] . Inactivated influenza vaccine can be safely and effectively administered during any trimester of pregnancy. No study to date has demonstrated an increased risk of either maternal complications or adverse fetal outcomes associated with inactivated influenza vaccination. Moreover, no scientific evidence exists that thimerosal-containing vaccines are a cause of adverse events among children born to women who received influenza vaccine during pregnancy [23] . Maternal influenza immunization is a highly cost-effective intervention at disease rates and severity that correspond to both seasonal influenza epidemics and occasional pandemics. These findings justify ongoing efforts to optimize influenza vaccination during pregnancy from an economic perspective [24] .