title: Screening for aneuploidy in twins and higher-order multiples: is first-trimester nuchal translucency the solution?
abstract: Screening for aneuploidy in twins and higher-order multiples present complex practical and ethical issues that limit its provision to women. We review the currently available screening options and compare the merits and disadvantages of each method. The available diagnostic tests and therapeutic interventions for screen positive cases are also reviewed.
  
  
  BACKGROUND
  Obstetricians & Gynecologists, Family Physicians.
  
  
  OBJECTIVE
  After completion of this article, the reader will be able to list the various screenings for Down syndrome during pregnancy, to outline the advantages and disadvantages of each screening method, and to summarize the challenges in screening for aneuploidy in twins.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA. aodibo@mail.obgyn.upenn.edu
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Odibo
authors.forename: Kirsten
authors.initials: K
authors.lastname: Lawrence-Cleary
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
mesh_terms: D000782:Aneuploidy; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008423:Maternal Age; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis; D014427:Twins