title: Ultrasound in pregnancy and non-right handedness: meta-analysis of randomized trials.
abstract: OBJECTIVE
  To study the association between exposure to ultrasound in pregnancy and non-right handedness in children with available data from randomized trials.
  
  
  METHODS
  Follow-up data of 8865 children aged 8-14 years from three randomized trials on routine ultrasonography at 15-20 weeks' gestation were available. Handedness was assessed through questionnaires to the parents and classified according to five, 10 or 11 questions. Children not classified as right handed were regarded as non-right handed.
  
  
  RESULTS
  There was a statistically significant increased prevalence of non-right handedness in ultrasonographically screened children compared with controls (odds ratio (OR) 1.15; 95% CI, 1.03-1.29). The results in subgroups according to gender are consistent with the overall results, with no significant differences between boys and girls. Among boys, the association became stronger when an exploratory analysis according to ultrasound exposure before 19-22 weeks' gestation was done (OR 1.30; 95% CI, 1.10-1.53).
  
  
  CONCLUSIONS
  There is a statistically significant-albeit weak-association between ultrasound screening during pregnancy and being non-right handed later in life.
authors.affiliation: National Center for Fetal Medicine, St. Olav University Hospital of Trondheim, Norway. pepes@ntnu.no
authors.forename: K Å
authors.initials: KÅ
authors.lastname: Salvesen
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D016032:Randomized Controlled Trials as Topic; D012016:Reference Values; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D016216:Ultrasonography, Prenatal / Q000009:adverse effects