van den Eijnden MHA de Kleine RH de Blaauw I Peeters PMJG Koot BGP Oomen MWN Sloots CEJ van Gemert WG van der Zee DC van Heurn LWE Verkade HJ Wilde JCH Hulscher JBF 2017 INTRODUCTION Choledochal malformations (CMs) are increasingly diagnosed antenatally. There is a dilemma between early surgery to prevent CM-related symptoms and postponing surgery to reduce complications. We aimed to identify the optimal timing of surgery in asymptomatic neonates with antenatally diagnosed CM and to identify predictors for development of symptoms. METHODS Using the Netherlands Study group on CHoledochal Cyst/malformation (NeSCHoc) we retrospectively collected demographic, biochemical and surgical data from all Dutch patients with an antenatally detected CM. RESULTS Between 1989 and 2014, antenatally suspected CM was confirmed in 17 patients at a median age of 10days (1day-2months). Four patients developed symptoms directly after birth (24%). Thirteen patients (76%) remained asymptomatic. Two of these progressed to symptoms before surgical intervention at 0.7 and 2.1months resp. Postoperatively, four patients developed short-term complications and three developed long-term complications. Patients <5.6kg (the series median) showed more short-term complications (66%) when compared to patients >5.6kg (0%, p=0.02). CONCLUSION When not symptomatic within the first days of life, the majority of children with antenatally detected CM remains asymptomatic. Surgery might safely be delayed to the age of 6months or a weight of 6kg. Postponing surgery in the clinically and biochemical asymptomatic patient might decrease the complication rate. LEVELS OF EVIDENCE Level III. https://sonar.ch/global/documents/46676 eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jpedsurg.2017.03.003 info:eu-repo/semantics/altIdentifier/pmid/28318597 Journal of pediatric surgery. - 2017 Antenatal diagnosis Choledochal cysts Choledochal malformation Adult Child Choledochal Cyst Cohort Studies Female Humans Infant Infant, Newborn Male Netherlands Prenatal Diagnosis Retrospective Studies Time Factors Treatment Outcome The timing of surgery of antenatally diagnosed choledochal malformations: A descriptive analysis of a 26-year nationwide cohort. http://purl.org/coar/resource_type/c_6501