TY - JOUR T1 - Case-control study of prenatal ultrasonography exposure in children with delayed speech JF - Canadian Medical Association Journal JO - CMAJ SP - 1435 LP - 1440 VL - 149 IS - 10 AU - J. D. Campbell AU - R. W. Elford AU - R. F. Brant Y1 - 1993/11/15 UR - http://www.cmaj.ca/content/149/10/1435.abstract N2 - OBJECTIVE: To determine whether there is an association between prenatal ultrasound exposure and delayed speech in children. DESIGN: Case-control study. SETTING: Network of community physicians affiliated with the Primary Care Research Unit, University of Calgary. SUBJECTS: Thirty-four practitioners identified 72 children aged 24 to 100 months who had undergone a formal speech-language evaluation and were found to have delayed speech of unknown cause by a speech-language pathologist. For each case subject the practitioners found two control subjects matched for sex, date of birth, sibling birth order and associated health problems. MAIN OUTCOME MEASURES: Rates of prenatal ultrasound exposure and delayed speech. RESULTS: The children with delayed speech had a higher rate of ultrasound exposure than the control subjects. The findings suggest that a child with delayed speech is about twice as likely as a child without delayed speech to have been exposed to prenatal ultrasound waves (odds ratio 2.8, 95% confidence limit 1.5 to 5.3; p = 0.001). CONCLUSION: An association between prenatal ultrasonography exposure and delayed speech was found. If there is no obvious clinical indication for diagnostic in-utero ultrasonography, physicians might be wise to caution their patients about the vulnerability of the fetus to noxious agents. ER -