[1] Katholieke Univ Leuven Hosp, Fetal Med Unit, Louvain, Belgium
[2] Hosp Clin Barcelona, Barcelona, Spain
[3] Kings Coll Hosp London, London, England
[4] Univ Sydney, Royal Prince Alfred Hosp, Dept High Risk Obstet, Sydney, NSW 2006, Australia
[5] Childrens Hosp Philadelphia, Dept Surg, Philadelphia, PA 19104 USA