title: The risk of birth defects in children born after assisted reproductive technologies.
abstract: OBJECTIVE
  This review addresses the question of whether there is evidence of an increased risk of birth defects in children born following assisted reproductive technologies compared with spontaneously conceived children.
  
  
  RESULTS
  Three recent studies added relatively little new information given their modest size (56-472 assisted reproductive technology children). We therefore considered all published papers that compared birth defects in children born following assisted reproductive technologies with those in children born following spontaneous conception. Overall, only six of the 26 relevant papers concluded there was an increased risk of birth defects following assisted reproductive technologies. The interpretation of many studies was based on statistical significance testing alone. When results showed a greater proportion of defects in the assisted reproductive technology group compared with the spontaneous group, but the results were not statistically significant, this was often interpreted as showing no increase in risk, rather than an increase in risk that may have been due to chance. The vast majority of individual studies were too small to have sufficient power to detect, as statistically significant, clinically relevant results. We found that although only eight (30%) of the studies had statistically significant results, 24 (89%) had an odds ratio estimate comparing assisted reproductive technology with spontaneously conceived children of over 1.0; 19 (70%) had an estimate of 1.20 or greater; and 14 (52%) had an estimate of 1.5 or greater.
  
  
  CONCLUSIONS
  Current evidence suggests there is an elevated risk of birth defects in children born following assisted reproductive technologies. Whilst others may disagree with our interpretation, one certainly cannot exclude this possibility on the basis of the current evidence.
authors.affiliation: National Perinatal Epidemiology Unit, University of Oxford, UK. jenny.kurinczuk@perinat.ox.ac.uk
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Kurinczuk
authors.forename: Michèle
authors.initials: M
authors.lastname: Hansen
authors.forename: Carol
authors.initials: C
authors.lastname: Bower
mesh_terms: D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D007231:Infant, Newborn; D027724:Reproductive Techniques, Assisted; D012307:Risk Factors