title: International trends of Down syndrome 1993-2004: Births in relation to maternal age and terminations of pregnancies.
abstract: BACKGROUND
  The aim of this study was to examine trends of Down syndrome (DS) in relation to maternal age and termination of pregnancies (ToP) in 20 registries of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR).
  
  
  METHODS
  Trends of births with DS (live-born and stillborn), ToP with DS, and maternal age (percentage of mothers older than 35 years) were examined by year over a 12-year period (1993-2004). The total mean number of births covered was 1550,000 annually.
  
  
  RESULTS
  The mean percentage of mothers older than 35 years of age increased from 10.9% in 1993 to 18.8% in 2004. However, a variation among the different registers from 4-8% to 20-25% of mothers >35 years of age was found. The total mean prevalence of DS (still births, live births, and ToP) increased from 13.1 to 18.2/10,000 births between 1993 and 2004. The total mean prevalence of DS births remained stable at 8.3/10,000 births, balanced by a great increase of ToP. In the registers from France, Italy, and the Czech Republic, a decrease of DS births and a great increase of ToP was observed. The number of DS births remained high or even increased in Canada Alberta, and Norway during the study period.
  
  
  CONCLUSIONS
  Although an increase in older mothers was observed in most registers, the prevalence of DS births remained stable in most registers as a result of increasing use of prenatal diagnostic procedures and ToP with DS.
authors.affiliation: Istituto Clinico di Pediatria Preventiva e Neonatologia, Bologna, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Cocchi
authors.forename: Silvia
authors.initials: S
authors.lastname: Gualdi
authors.forename: Caroline
authors.initials: C
authors.lastname: Bower
authors.forename: Jane
authors.initials: J
authors.lastname: Halliday
authors.forename: Björn
authors.initials: B
authors.lastname: Jonsson
authors.forename: Asa
authors.initials: A
authors.lastname: Myrelid
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Mastroiacovo
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Amar
authors.forename: Marian K
authors.initials: MK
authors.lastname: Bakker
authors.forename: Andrea
authors.initials: A
authors.lastname: Correa
authors.forename: Berenice
authors.initials: B
authors.lastname: Doray
authors.forename: Kari Klungsør
authors.initials: KK
authors.lastname: Melve
authors.forename: Babak
authors.initials: B
authors.lastname: Koshnood
authors.forename: Daniella
authors.initials: D
authors.lastname: Landau
authors.forename: Osvaldo M
authors.initials: OM
authors.lastname: Mutchinick
authors.forename: Anna
authors.initials: A
authors.lastname: Pierini
authors.forename: Anukka
authors.initials: A
authors.lastname: Ritvanen
authors.forename: Vera
authors.initials: V
authors.lastname: Ruddock
authors.forename: Giocchino
authors.initials: G
authors.lastname: Scarano
authors.forename: Barbara
authors.initials: B
authors.lastname: Sibbald
authors.forename: Antonin
authors.initials: A
authors.lastname: Sípek
authors.forename: Romano
authors.initials: R
authors.lastname: Tenconi
authors.forename: Dave
authors.initials: D
authors.lastname: Tucker
authors.forename: Göran
authors.initials: G
authors.lastname: Annerén
mesh_terms: D000028:Abortion, Induced; D004314:Down Syndrome / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D015995:Prevalence