Part of the ultrasound machine safety guide....
In February 2004, the American Food and Drug Administration (FDA) delivered the following statement:
Persons, who promote, sell or lease ultrasound equipment for making “keepsake” fetal videos should know that FDA views this as an unapproved use of a medical device.
Additionally, individuals whom subject others to ultrasound exposure using a diagnostic ultrasound device while lacking a physician’s prescription may be in violation of state or local laws or regulations regarding use of a prescription medical device.
So who is right? Those who state the ultrasound is perfectly safe, or those who suggest they be used with caution. Why is there such concern surrounding technology that has been in everyday use for so many years?
The Impact of Ultrasound Machine Use on Fetal Tissue
Ultrasound is a form of energy—sound waves vibrate at roughly a hundred times the frequency of normal sound— these waves can have a variety of effects on fetal tissue. Heat is just one effect. Moreover, although ultrasound doesn’t produce audible noise, secondary vibrations can produce sounds as loud as 100 decibels; this causes the fetus to move.
Further effects, not yet thoroughly understood, include tiny bubbles in tissue (a process known as cavitation), sheering forces within tissues, induced flows within fluids, and development of minute quantities of toxic chemicals.
Ethical restrictions prevent any direct studies of ultrasound effects on humans. Scientists are using animal studies in addition to data from populations of humans previously exposed to ultrasound.
According to one study in 1998, increases in temperature of four and a half degrees Centigrade (8.1 degrees Fahrenheit) were measured in the brain of heavily pregnancy live guinea-pig fetuses insinuated in utero for 2 minutes by pulsed Doppler-type ultrasound. Further studies using guinea-pig have revealed adverse effects on cell division in bone marrow following exposure to ultrasound.
In October 2004, Chairman of the Neurobiology Department at Yale University, announced that he and his colleagues had witnessed some disruption of normal migration of cells in the brains of fetal mice after being exposed to ultrasound. He is now undertaking a $3 million study to determine whether the same effects occur in the offspring of rhesus macaque monkeys scanned during pregnancy. Such disruption in humans is known to be caused by certain viruses, mutations, and drugs, and is linked to a range of disorders including autism and learning disabilities.
In 2001, a team of Polish researchers published actual temperature readings taken from an adult human brain during exposure to ultrasound machine waves. The results showed no increase in temperature, causing the researchers to conclude that the human brain has superior cooling capacities than the brains of smaller mammals.
However it remains unknown whether the rapidly developing brain of the human fetus is also protected from induced heat from a prenatal ultrasound. In order to establish whether such heating may cause subtle brain damage in human populations, scientists have tried to compare the health histories of children exposed to ultrasound and the same data for children not exposed.
Up to now, studies of humans exposed to 3d ultrasound machine waves have shown a number of possible adverse effects: growth retardation, dyslexia, and delayed speech development. However, only one effect, a higher rate of left-handedness amongst boys who were exposed to ultrasound technology whilst in the womb, has been observed in at least three individual studies.