In the study period, 152 children were treated for anorectal malformations in our hospital; treatment of 8 of them had been initiated elsewhere. Eleven children died at a young age due to severe comorbidity: 3 patients had a complex cardiac malformation and died of postoperative cardiac complica- tions, 3 patients with multiple malformations (including
cerebral abnormalities) died from sepsis, and only supportive care was given in 3 patients with a cloacal exstrophy; 2 of these patients had trisomy 18 and one patient had Pallister Hall syndrome. Twenty-seven children were lost to follow- up, and parents of 6 did not enter the child in the follow-up program, resulting in 108 children included for this study. The baseline characteristics of the 33 children not seen in follow-up did not differ from those included in this study (not shown). The baseline characteristics of the 108 included children are shown in Table 1. Note the almost equal distribution of the type of malformation: 51% had a low malformation. At least one additional major comorbidity was documented in 46%. Other GI-disorders related to persisting growth problem were mainly esophageal atresia (n = 9), and the need of a gastrostomy for serious feeding disorders (n = 4). Twenty-two children did not undergo correcting surgery: 18 had a low malformation requiring Hegar dilatation only; 4 had a high malformation for which a permanent colostomy was done. Four patients had a suspected syndromal diagnosis: 2 Cat eye syndrome, 1 Townes–Brocks syndrome, 1 Bardet– Biedl syndrome, they had all been included because the diagnosis was not confirmed.