The medical management of infants with the trisomy 13 and trisomy 18 syndromes is challenging and controversial. Both conditions have high neonatal and infant mortality, and surviving children display significant cognitive and motor disabilities. Currently, there exists a tension in the neonatal and perinatal communities regarding care. One view holds that management should consist solely of comfort care, while another opinion recommends offering medical and surgical intervention in appropriate situations. The purpose of this manuscript is to present a model for the care of fetuses and infants with trisomy 13 and 18 during the prenatal, perinatal, and postnatal periods. Adopting the pathways approach as a framework, we have identified several pertinent decision points, characterizing the goals of care and the resources needed for the decision points at various times. Additionally, we identified themes surrounding parental and professional experiences. The authors propose a care model for trisomy 13 and 18 that uses shared decision making as its foundational principle and the pathways approach as the method. Our model requires further investigation as a strategy for care in order to render it useful in other complex medical situations. (c) 2016 Wiley Periodicals, Inc.