Routine ultrasound screening in pregnancy and the children's subsequent neurologic development

To test the null hypothesis of no association between ultrasound exposure in early fetal life and impaired neurologic development in childhood.

Study of children age 8-9 years whose mothers participated in a randomized controlled trial of ultrasound screening during pregnancy in Sweden during 1985-1987. Of 4637 eligible singletons, 3265 (70%) were studied through a questionnaire to their mothers. Assessment of neurologic development was based on parents' report of their child's speech and motor development. Behavioral disorders were assessed by a ten-item parent scale. Analyses were performed according to both assignment and ultrasound exposure. With a sample size of 1600 children in each group, a two-sided alpha of .05 and beta of .10, a risk ratio of less than 1.4 for the studied variables could not be detected.

Delayed speech development was reported by 2.9% in the screening group compared with 2.4% in the nonscreening group (odds ratio [OR] 1.21; 95% confidence interval [CI] 0.79, 1.88). Similar prevalences were found when analysis was according to ultrasound exposure (OR 1.19, 95% CI 0.78, 1.83). Delayed motor development was reported by 7.6% in the screening group compared with 7.2% in the nonscreening group (OR 1.05; 95% CI 0.81, 1.37). Corresponding figures for ultrasound-exposed and -unexposed were 7.7% and 7.2%, respectively (OR 1.08; 95% CI 0.83, 1.40). There also were no significant differences in behavioral disorders between screened and unscreened children or between exposed and unexposed children, respectively, according to parents' ratings.

No significant difference in impaired neurologic development between ultrasound-exposed and -unexposed children was found in this study.