title: Antenatal detection of Edwards (Trisomy 18) and Patau (Trisomy 13) syndrome: England and Wales 2005-2012.
abstract: OBJECTIVE
  Pregnancies with Edwards or Patau syndrome are often detected through screening for Down's syndrome. We aimed to evaluate the impact of screening for Down's syndrome on the prevalence of live births and antenatal diagnoses of Edwards and Patau syndrome.
  
  
  METHODS
  England and Wales, 2005 to 2012.
  
  
  METHODS
  Data from the National Down Syndrome Cytogenetic Register, which contains information on nearly all ante- or postnatally diagnosed cases of Edwards or Patau syndrome in which a karyotype was confirmed, were analysed.
  
  
  RESULTS
  From 2005 to 2012, 3,941 diagnoses of Edwards syndrome and 1,567 diagnoses of Patau syndrome were recorded (prevalence of 7.0 and 2.8 per 10,000 births respectively). Only 11% (95% confidence interval [CI]: 10-12) of diagnoses of Edwards syndrome and 13% (95% CI: 11-14) of Patau syndrome were live births, resulting in live birth prevalences of 0.8 (95% CI: 0.7-0.8) and 0.4 (95% CI: 0.3-0.4) per 10,000 live births respectively. About 90% of pregnancies with Edwards or Patau syndrome were diagnosed antenatally, and this proportion remained constant over time. The proportion of diagnoses detected before 15 weeks increased from 50% in 2005 to 53% in 2012 for Edwards syndrome, and from 41% in 2005 to 63% in 2012 for Patau syndrome.
  
  
  CONCLUSIONS
  Almost 700 women per year had a pregnancy with Edwards or Patau syndrome. Over 90% of these pregnancies were detected antenatally, with the increased use of first trimester screening for Down's syndrome resulting in the reduction in the mean gestational age at diagnosis of these syndromes.
authors.affiliation: Centre for Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Springett
authors.affiliation: Centre for Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, EC1M 6BQ j.k.morris@qmul.ac.uk.
authors.forename: Joan K
authors.initials: JK
authors.lastname: Morris
mesh_terms: D000328:Adult; D025063:Chromosome Disorders / Q000175:diagnosis* / Q000453:epidemiology; D002882:Chromosomes, Human, Pair 13; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000175:diagnosis; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D007621:Karyotyping; D011247:Pregnancy; D011296:Prenatal Diagnosis; D015995:Prevalence; D012042:Registries; D014314:Trisomy / Q000175:diagnosis*; D000073839:Trisomy 13 Syndrome; D000073842:Trisomy 18 Syndrome; D014852:Wales / Q000453:epidemiology
keywords: Antenatal detection; Edwards syndrome; Patau syndrome; Prenatal screening; Trisomy 13; Trisomy 18