Objective To test a hypothesis of no association between ultrasound exposure in early fetal life and growth or impaired vision or hearing during childhood.
Design Follow up of eight to nine year old children born to women who participated in a randomised controlled trial on ultrasound screening during pregnancy.
Setting Nineteen antenatal care clinics run by three central hospitals in Sweden from 1985 to 1987.
Population and methods Of 4637 eligible singleton pregnancies, 3265 (71%) were followed up through a questionnaire sent to their mothers. Analyses were performed both according to randomised groups and to ultrasound exposure.
Main outcome measures Parents’ report of vision and hearing tests as recorded on child's record card. Parents’ report of their child's weight and height at 1, 4 and 7 years of age.
Results Reduced hearing was reported by 3.4% in the screening group compared with 3.5% in the nonscreening group (odds ratio [OR] 1.0; 95% confidence interval [CI] 0.67–1.41). The same prevalences were found when analysed according to ultrasound exposure (OR 1.0; 95% CI 0.67–1.42). Reduced vision was reported by 6.3% in the screening group compared with 7.8% in the nonscreening group (OR 0.8; 95% CI 0.60–1.03). Corresponding figures for ultrasound exposed and unexposed were 6.2% and 8.0%, respectively (OR 0.8; 95% CI 0.58–1.00). No statistically significant differences in body weight or height at 1, 4 or 7 years of age between screened and not screened children or between exposed and unexposed were found.
Conclusion This study found no association between ultrasound exposure in early fetal life and growth or impaired vision or hearing during childhood.