title: Prenatal ultrasound exposure and children's school performance at age 15-16: follow-up of a randomized controlled trial.
abstract: OBJECTIVE
  To evaluate the association between prenatal ultrasound exposure and school performance at 15-16 years of age.
  
  
  METHODS
  The study population consisted of children born to women who participated in a randomized controlled trial on the second-trimester ultrasound examination in Sweden from 1985 to 1987. Information about the children's grades when graduating from primary school and information on socioeconomic factors was obtained from Swedish nationwide registers. Comparisons were made using linear and logistic regression analyses according to randomization to ultrasound, ultrasound exposure in the second trimester and ultrasound exposure at any time during pregnancy. Boys and girls were analyzed separately.
  
  
  RESULTS
  Of the 4756 singleton children from the randomized trial, we identified 4458 (94%) in the National School Register. There were no statistically significant differences in school performance for boys or girls according to randomization or exposure to ultrasound in the second trimester. Compared to those who were unexposed, boys exposed to ultrasound at least once at any time during fetal life had a tendency towards lower mean school grades in general (-4.39 points; 95% CI, -9.59 to 0.81 (max possible, 320) points) and in physical education (-0.45 points; 95% CI, -0.91 to 0.01 (max possible, 20) points), but the differences did not reach significance.
  
  
  CONCLUSIONS
  In general, routine ultrasound examination in the second trimester had no effect on overall school performance in teenagers.
authors.affiliation: Department of Women's and Children's Health, Obstetrics and Gynaecology, Uppsala University, Uppsala S-751 85, Sweden. karin.stalberg@kbh.uu.se
authors.forename: K
authors.initials: K
authors.lastname: Stålberg
authors.forename: O
authors.initials: O
authors.lastname: Axelsson
authors.forename: B
authors.initials: B
authors.lastname: Haglund
authors.forename: C M
authors.initials: CM
authors.lastname: Hultman
authors.forename: M
authors.initials: M
authors.lastname: Lambe
authors.forename: H
authors.initials: H
authors.lastname: Kieler
mesh_terms: D000293:Adolescent; D002648:Child; D002657:Child Development / Q000502:physiology*; D004522:Educational Status; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000503:physiopathology*; D013548:Sweden / Q000453:epidemiology; D016216:Ultrasonography, Prenatal / Q000009:adverse effects*