[1] Univ Med Ctr Utrecht, Wilhelmina Childrens Hosp, Dept Obstet, Div Woman & Baby, Utrecht, Netherlands
[2] Univ Med Ctr Utrecht, Wilhelmina Childrens Hosp, Dept Pediat Surg, Utrecht, Netherlands
[3] Isala Hosp Zwolle, Dept Obstet, Div Woman & Baby, Zwolle, Netherlands
[4] Acad Med Ctr, Dept Clin Epidemiol Biostat & Bioinformat, Amsterdam, Netherlands