title: First trimester anatomy scan: pushing the limits. What can we see now?
abstract: OBJECTIVE
  The aim of this review article is to familiarize the reader with the current developments dealing with ultrasound during the first trimester of pregnancy.
  
  
  RESULTS
  The main emphasis of this article is to review the anatomy seen during the first trimester and to bring to the reader the fact that the first anatomical survey of the fetus does not have to wait until the 18th to 20th week of gestation. The fetus can be surveyed adequately as early as the 12th week of gestation and ideally between the 13th and 14th weeks. Of course, not all malformations will be detected during the first trimester, and a follow-up scan between 20 and 23 weeks is indicated.
  
  
  CONCLUSIONS
  The ongoing improvements in ultrasound technology allow us to see more details of the embryo or fetus at earlier gestational ages than ever before. This is resulting in a rethinking of when the first anatomical survey should be performed.
authors.affiliation: Department of Obstetrics and Gynecology, New York University School of Medicine, New York, New York, USA. Ana.Monteagudo@med.nyu.edu
authors.forename: Ana
authors.initials: A
authors.lastname: Monteagudo
authors.forename: Ilan E
authors.initials: IE
authors.lastname: Timor-Tritsch
mesh_terms: D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D016216:Ultrasonography, Prenatal