Snapshot A 41-year-old G3P1 presents to clinic 11 weeks pregnant. She has a history of 1 miscarriage and 1 uncomplicated live birth with no complications 10 years ago. Her daughter is healthy. She has no medical conditions. Vital signs are within normal limits. She receives first-trimester screening and a cell-free DNA test. Introduction Overview login to view 1 more bullet Epidemiology Incidence login to view 1 more bullet Risk factors login to view 2 more bullets Pathogenesis Most from nondisjunction Some due to somatic mosaicism or translocations Studies First-trimester screening login to view 28 more bullets Second-trimester screening login to view 25 more bullets Sequential integrated screening login to view 10 more bullets Cell-free DNA login to view 6 more bullets