[1] Univ Zurich Hosp, Clin & Policlin Obstet, Dept Obstet & Gynecol, CH-8091 Zurich, Switzerland
[2] Univ Zurich Hosp, Transfus Med Sect, Dept Internal Med, CH-8091 Zurich, Switzerland
[3] Univ Zurich Hosp, Inst Clin Pathol, CH-8091 Zurich, Switzerland