BACKGROUND: Congenital pericardial defects occur from a defect in the formation of the pleuropericardial membrane during embryonic development. This defect may be asymptomatic but can be fatal if complicated by herniation of any portion of the heart.
CASES: We report two cases in which herniation of a portion of the heart occurred through a partial left pericardial defect and resulted in fetal death. In case one, there were no fetal symptoms, and in case two, an irregular heartbeat was detected prompting a fetal echocardiogram that was negative for heart abnormalities.
CONCLUSION: Although isolated congenital pericardial defects are rare, they can result in fetal death. Awareness may help to refine ultrasonography or other diagnostic modalities to evaluate possible congenital pericardial defects in utero.