title: Association between congenital foot anomalies and gestational age at amniocentesis.
abstract: OBJECTIVE
  Our objectives were to confirm the reported association between early amniocentesis and congenital foot anomalies as well as to report, for the first time, on the outcome of amniocenteses performed during the 13th and 14th weeks of gestation.
  
  
  METHODS
  We conducted a triple cohort retrospective study of 4457 amniocenteses. Cohort definitions: early amniocentesis (EA), 11 weeks and 0/7 days to 12 weeks to 6/7 days; early midtrimester amniocentesis (EMA), 13 weeks and 0/7 days to 14 weeks and 6/7 days; and midtrimester amniocentesis (MA), 15 weeks and 0/7 days to 19 weeks and 6/7 days. Outcome measures were obtained by searching the Alberta Congenital Anomalies Surveillance System (ACASS) database for children born with foot anomalies represented by International Classification of Diseases version 9 (ICD-9) codes 754.5, 754.6 and 754.7.
  
  
  RESULTS
  Incidences of congenital foot anomalies were: EA 11/980 (1.1%), EMA 11/2515 (0.4%), and MA 1/962 (0.1%). There is a significant difference between the EA and EMA cohorts (p=0.019) and between the EA and MA cohorts (p=0.003); however, these data suggest there is no difference between EMA and MA cohorts (p=0.11).
  
  
  CONCLUSIONS
  Our incidence of congenital foot anomalies of 1.1% for women who underwent EA is similar to previously reported data, which further validates this association; however, our data also suggest that the foot anomaly risk may be limited to amniocenteses performed before the 13th week of gestation.
authors.affiliation: Department of Medical Genetics, University of Calgary, Canada.
authors.forename: G
authors.initials: G
authors.lastname: Yoon
authors.forename: J
authors.initials: J
authors.lastname: Chernos
authors.forename: B
authors.initials: B
authors.lastname: Sibbald
authors.forename: R B
authors.initials: RB
authors.lastname: Lowry
authors.forename: G
authors.initials: G
authors.lastname: Connors
authors.forename: R
authors.initials: R
authors.lastname: Simrose
authors.forename: F P
authors.initials: FP
authors.lastname: Bernier
mesh_terms: D000649:Amniocentesis / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D005532:Foot Deformities, Congenital / Q000453:epidemiology* / Q000209:etiology; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D012189:Retrospective Studies