CASE-CONTROL STUDY OF PRENATAL ULTRASONOGRAPHY EXPOSURE IN CHILDREN WITH DELAYED SPEECH

Objective: To determine whether there is an association between prenat al ultrasound exposure and delayed speech in children. Design: Case-co ntrol study. Setting: Network of community physicians affiliated with the Primary Care Research Unit, University of Calgary. Subjects: Thirt y-four practitioners identified 72 children aged 24 to 100 months who had undergone a formal speech-language evaluation and were found to ha ve delayed speech of unknown cause by a speech-language pathologist. F or each case subject the practitioners found two control subjects matc hed 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 h igher rate of ultrasound exposure than the control subjects. The findi ngs suggest that a child with delayed speech is about twice as likely as a child without delayed speech to have been exposed to prenatal ult rasound waves (odds ratio 2.8 95% confidence limit 1.5 to 5.3; p = 0.0 01). Conclusion: An association between prenatal ultrasonography expos ure and delayed speech was found. If there is no obvious clinical indi cation for diagnostic in-utero ultrasonography, physicians might be wi se to caution their patients about the vulnerability of the fetus to n oxious agents.