Svenningsson A, et al. - Researchers sought to determine maternal risk factors and perinatal characteristics of patients with anorectal malformations (ARM) in Sweden. All patients with ARM born in Sweden 1973–2014 were included in this population-based case–control study. For ARM, maternal obesity was identified to be a possible risk factor. Prematurity and small for gestational age were noted more commonly among ARM patients. In patients without associated malformations, maternal smoking was also suggested to be a risk factor of ARM.