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 asseses if fetus has a genetic condition Epidemiology Incidence 1/150 live births with chromosomal abnormalities Risk factors advanced maternal age history of prior fetal aneuploidy or abnormality Pathogenesis Most from nondisjunction Some due to somatic mosaicism or translocations Studies First-trimester screening indications login to view 1 more bullet serum labs login to view 8 more bullets imaging login to view 4 more bullets invasive studies login to view 11 more bullets Second-trimester screening indications login to view 1 more bullet serum labs login to view 13 more bullets invasive studies login to view 8 more bullets Sequential integrated screening first trimester login to view 5 more bullets second trimester login to view 2 more bullets higher detection rates than either first or second trimester screening alone Cell-free DNA indications login to view 3 more bullets highest detection rate for Down syndrome higher false-positive rate for low-risk patients