[1] Royal Brompton Hosp, London SW3 6LY, England
[2] St George Hosp, Fetal Med Unit, London, England
[3] St Georges Univ London, London, England
[4] Kings Coll Hosp London, Harris Birthright Res Ctr Fetal Med, London, England
[5] Ctr Prenatal Diag & Human Genet, Berlin, Germany
[6] Yale Univ, Sch Med, New Haven, CT USA
[7] Fetal Diagnost Ctr, Pasadena, CA USA
[8] Univ Calif Los Angeles, David Geffen Sch Med, Dept Obstet & Gynecol, Los Angeles, CA 90095 USA
[9] Univ Med Ctr Hamburg Eppendorf, Dept Obstet & Fetal Med, Hamburg, Germany
[10] Baylor Coll Med, Dept Obstet & Gynecol, Houston, TX 77030 USA
[11] Univ Chile, Fetal Med Unit, Obstet & Gynecol Dept, Santiago, Chile
[12] Clin Las Condes, Santiago, Chile
[13] Univ Naples Federico II, Fetal Med & Cardiol Unit, Dept Obstet & Gynecol, Naples, Italy
[14] Ctr Fetal Med & Gynecol Ultrasound, Basel, Switzerland
[15] Univ Dusseldorf, Fac Med, D-40225 Dusseldorf, Germany
[16] Hadassah Hebrew Univ Med Ctr, Div Obstet & Gynecol, Jerusalem, Israel