Two rare cases of infants born from pregnancies complicated by large placental chorioangiomas are reported. Congestive heart failure occurred early in the neonatal period as the main complication. Chorioangiomas may be diagnosed early in pregnancy by ultrasound examination. Since both maternal and neonatal complications may indicate premature termination of the pregnancy or be conducive to premature birth, repeated ultrasound examinations, including fetal echocardiography and flow measurements, are suggested to determine the optimal time of delivery. Possible pathophysiological mechanisms causing neonatal complications are discussed.