title: Ultrasound during pregnancy and subsequent childhood non-right handedness: a meta-analysis.
abstract: OBJECTIVE
  A possible association between ultrasound during pregnancy and subsequent non-right handedness among children has been suggested. The association has been reported to be stronger among boys. The aim of the present study was to explore this further through a meta-analysis of two follow-up studies of three randomized controlled trials of routine ultrasonography during pregnancy.
  
  
  METHODS
  Handedness was assessed through a questionnaire to the parents, and 4715 children at the age of 8-9 years were included in the meta-analysis.
  
  
  RESULTS
  There was no statistically significant difference in the prevalence of non-right handedness between the ultrasound-screened children and the controls, but there was a statistically significant difference in a subgroup analysis among the boys. Exploratory analyses according to exposure or non-exposure indicated an even stronger association between ultrasound and non-right handedness.
  
  
  CONCLUSIONS
  A conservative analytical approach indicates no association between ultrasound in utero and subsequent non-right handedness. The results from the exploratory analyses must be interpreted with caution. There is still a need for further research.
authors.affiliation: Department of Obstetrics and Gynecology, Trondheim University Hospital, Norway.
authors.forename: K A
authors.initials: KA
authors.lastname: Salvesen
authors.forename: S H
authors.initials: SH
authors.lastname: Eik-Nes
mesh_terms: D000328:Adult; D002648:Child; D005314:Embryonic and Fetal Development; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009664:Norway; D016017:Odds Ratio; D011247:Pregnancy; D012016:Reference Values; D012680:Sensitivity and Specificity; D012727:Sex Characteristics; D016216:Ultrasonography, Prenatal / Q000009:adverse effects*