title: A population-based evaluation of antenatal diagnosis of orofacial clefts.
abstract: OBJECTIVE
  To evaluate the changes in prevalence and antenatal detection of cleft lip with or without cleft palate and isolated cleft palate and to describe the association between anomalies and rates of antenatal diagnosis in Nova Scotia from 1992 to 2002.
  
  
  METHODS
  This population-based cohort study employed the Nova Scotia Atlee Perinatal Database, the Fetal Anomaly Database, and IWK Cleft Palate Database in Halifax, Nova Scotia, Canada.
  
  
  METHODS
  Cleft type, mode of diagnosis, and associated abnormalities of orofacial clefts for liveborn infants, stillbirths, and second trimester terminations of pregnancy between 1992 and 2002 were determined.
  
  
  RESULTS
  There were 225 fetuses identified as having orofacial clefts. The overall prevalence of clefts was 2.1 in 1000 live births, and this prevalence did not change with time. The overall antenatal detection of cleft lip with or without cleft palate was 23%; however, there was improvement in detection of cleft lip with or without cleft palate from the years 1992 to 1996 (14%) to the years 1997 to 2002 (30%, p = .02). No isolated cleft palates were detected antenatally. Associated structural anomalies were seen in 34.2% of cases with orofacial clefts, and chromosomal abnormalities were associated with 9.8%.
  
  
  CONCLUSIONS
  The prevalence of orofacial clefts in Nova Scotia has not changed from 1992 to 2002. The proportion of antenatally diagnosed cleft lip with or without cleft palate in Nova Scotia is consistent with rates reported in the literature and has increased from 1992 to 2002.
authors.affiliation: Division of Orthodontics, Faculty of Dentistry, Dalhousie University and IWK Health Centre, 5981 University Avenue, Halifax, Nova Scotia, Canada. Kathy.Russell@Dal.ca
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Russell
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Allen
authors.forename: Mary E
authors.initials: ME
authors.lastname: MacDonald
authors.forename: Kirsten
authors.initials: K
authors.lastname: Smith
authors.forename: Linda
authors.initials: L
authors.lastname: Dodds
mesh_terms: D000015:Abnormalities, Multiple / Q000453:epidemiology; D000028:Abortion, Induced / Q000706:statistics & numerical data; D000328:Adult; D002869:Chromosome Aberrations / Q000706:statistics & numerical data; D002971:Cleft Lip / Q000453:epidemiology*; D002972:Cleft Palate / Q000453:epidemiology*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005315:Fetal Diseases / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D050498:Live Birth / Q000453:epidemiology; D008423:Maternal Age; D009674:Nova Scotia / Q000453:epidemiology; D010298:Parity; D011159:Population Surveillance; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000706:statistics & numerical data*; D015995:Prevalence; D050497:Stillbirth / Q000453:epidemiology