CMAJ. 1993 Nov 15;149(10):1435-40.
Case-control study of prenatal ultrasonography exposure in children with delayed speech.
Campbell JD, Elford RW, Brant RF.
Department of Surgery, University of Calgary, Alta.
To determine whether there is an association between prenatal ultrasound exposure and delayed speech in children.
Network of community physicians affiliated with the Primary Care Research Unit, University of Calgary.
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.
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).
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.