title: Birth defect and risk factor surveillance in the northern and southwestern Netherlands.
abstract: OBJECTIVE
  To survey the associations between several risk factors and birth defects, in order to detect potential new teratogens.
  
  
  METHODS
  Data of the two Dutch European Registration of Congenital Anomalies (EUROCAT) registries collected before January 1, 1998 were used to perform chi2 tests for a large number of risk factors and birth defects. Defects caused by chromosomal or monogenic disorders were analyzed separately.
  
  
  RESULTS
  Cross-tabulations of 80 groups of birth defects with 303 risk factors were studied. Of these, 126 combinations had a p value under 0.05, and 34 had a p value under 0.001. Of these 34 associations, some are known in the literature, some were found before in the same databases and some were new associations.
  
  
  CONCLUSIONS
  This is a good method for generating new hypotheses for associations between risk factors and birth defects. It can be a start for new, more in-depth studies of potential teratogens.
authors.affiliation: EUROCAT Northern Netherlands, Department of Medical Genetics, University of Groningen, Groningen, The Netherlands. j.reefhusi@med.rug.nl
authors.forename: J
authors.initials: J
authors.lastname: Reefhuis
authors.forename: G R
authors.initials: GR
authors.lastname: Zandwijken
authors.forename: H E
authors.initials: HE
authors.lastname: De Walle
authors.forename: M C
authors.initials: MC
authors.lastname: Cornel