1. From the Fetal Maternal Medicine Unit (K.M., B.T.), Department of Obstetrics and Gynecology and the Department of Cardiology and Cardiothoracic Surgery (K.M., G.R.S., A.B.), St Georges Hospital, University of London, London, UK; and the Department of Obstetrics and Gynecology (K.M., M.L.), University of Chieti, Chieti, Italy.