In utero transmission of Influenza AH1N1

Influenza A pandemic (H1N1) 2009 was first detected in United States in April 2009. It is associated with high risk of complications in pregnant women and children. Transplacental infection of influenza A is rare. We report a case of in utero transmission of Influenza A (H1N1) infection in a newborn whose mother was seriously ill with Influenza A (H1N1) during the perinatal period. Our patient was likely infected in utero because he was delivered by cesarean section and was never exposed to his mother, who required intensive cardiopulmonary support at the time of delivery.