[1] Univ Hosp Zurich, Dept Obstet, Zurich, Switzerland
[2] Univ Zurich, Zurich, Switzerland
[3] Univ Zurich, Zurich Ctr Fetal Diag & Therapy, Zurich, Switzerland
[4] Univ Childrens Hosp Zurich, Spina Bifida Ctr, Zurich, Switzerland
[5] Univ Childrens Hosp Zurich, Childrens Res Ctr, Zurich, Switzerland
[6] Univ Children?s Hosp Zurich, Dept Pediat Surg, Zurich, Switzerland