Does prenatal ultrasound exposure influence the development of children?

The use of ultrasound in obstetrics nowadays is an integral part of prenatal care. As a non-invasive method it has a wide application for the detection of abnormalities. During the course of pregnancy the foetus may be exposed to ultrasound waves often several times. Presently it is not clear whether this has a negative effect on the health and development of children. A systematic review of scientific literature on possible harmful effects on child development of ultrasound investigation during pregnancy. Databases of scientific literature were screened through for publications dealing with the use of ultrasound on the development of children. Studies were included if they had been published since 1990. Sixteen studies were included in this review--13 randomised controlled trials, one cohort study, and two case-control studies. This included three for speech development, two for vision and hearing, one for school performance, three for handedness, and seven for birthweight and growth. All studies demonstrated that ultrasound examinations during pregnancy increased the risk of undesirable developmental outcomes. On average, the magnitude of such effects was minimal. However, most of the studies have some methodological defects, in particular, outcome measurements, overlooking possible bias and confounding factors, and statistical insufficiencies. It is concluded that there is no adverse effect of ultrasound examinations during pregnancy on child development outcomes.