title: Early fetal anatomy screening: who, what, when and why?
abstract: OBJECTIVE
  This article reviews the potential benefits and downsides of early anatomy screening.
  
  
  RESULTS
  There is increasing evidence that about 50% of severe fetal anomalies can be diagnosed prior to 14 weeks of gestation. 'Red flags' such as an increased nuchal or intracranial translucency, tricuspid valve regurgitation, a small biparietal diameter, a single umbilical artery or an abnormal retronasal triangle should raise the sonographer's suspicion of a congenital defect and warrant a more thorough fetal assessment, which often includes transvaginal scanning. Care should, however, be taken not to overinterpret first-trimester findings as false-positive rates of 3-4% have been reported. With more subtle findings, and especially if a heart defect is suspected, a sonographic reassessment after 15 weeks' gestation is indicated. Patients should be counseled that findings could worsen but also improve with time.
  
  
  CONCLUSIONS
  Basic fetal anomaly screening should be recommended, piggybacked on the routine first-trimester (aneuploidy screening) ultrasound, both for low and high-risk populations. First-trimester anatomy screening seems particularly useful in obese women, whose fetuses are difficult to screen at the midtrimester ultrasound and in multiple gestation. Noninvasive prenatal testing using cell-free fetal DNA can complement but should not replace first-trimester ultrasound.
authors.affiliation: Division of Woman and Child, Department of Obstetrics and Gynecology, Maternal-Fetal Medicine, University Hospitals Leuven, Leuven, Belgium.
authors.forename: Tim
authors.initials: T
authors.lastname: Van Mieghem
authors.forename: An
authors.initials: A
authors.lastname: Hindryckx
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Calsteren
mesh_terms: D025063:Chromosome Disorders / Q000175:diagnosis* / Q000196:embryology; D005260:Female; D005865:Gestational Age; D006330:Heart Defects, Congenital / Q000175:diagnosis* / Q000196:embryology; D006801:Humans; D018579:Patient Selection; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000379:methods*; D012307:Risk Factors