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labour, even without routine prenatal ultrasound (MIDIRS, 1995). The American College of Obstetricians, in their guidelines on routine ultrasound in low-risk pregnancy, conclude that: "In a population of women with low-risk pregnancies, neither a reduc- tion in perinatal morbidity [harm to babies around the time of birth] and mortality nor a lower rate of unnecessary interventions can be expected from routine diagnostic ultrasound. Thus ultra- sound should be performed for specific indications in low-risk pregnancy" (ACOG, 1997). labour, even without routine prenatal ultrasound (MIDIRS, 1995). study showed that babies exposed to five or more Doppler The American College of Obstetricians, in their guidelines on ultrasounds were 30% more likely to develop intra-uterine growth routine ultrasound in low-risk pregnancy, conclude that: "Ina retardation (IUGR)—a condition that ultrasound is often used to population of women with low-risk pregnancies, neither a reduc- detect (Newnham, 1993). tion in perinatal morbidity [harm to babies around the time of Two long-term randomised controlled trials, comparing birth] and mortality nor a lower rate of unnecessary interventions exposed and unexposed children's development at eight to nine can be expected from routine diagnostic ultrasound. Thus ultra- years old, found no measurable effect from ultrasound (Salvesen, sound should be performed for specific indications in low-risk 1992; Kieler, 1998b). However, as the authors note, intensities pregnancy" (ACOG, 1997). used today are many times higher than in 1979 to 1981. Further, in the major branch of one trial, scanning time was only three BIOLOGICAL EFFECTS OF ULTRASOUND minutes (Salvesen, 1993). More studies are obviously needed in Ultrasound waves are known to affect tissues in two main ways. this field, particularly in the areas of Doppler and vaginal ultra- Firstly, the sonar beam causes heating of the highlighted area by sound where exposure levels are much higher. about 1° Celsius. This is presumed to be non-significant, based A further problem with studying ultrasound's effects is the huge on whole-body heating in pregnancy, which seems to be safe up _ range of output, or dose, possible from a single machine. Modern to 2.5°C (American Institute of Ultrasound Medicine Bioeffects machines can give comparable ultrasound pictures using a lower Report, 1988). or a 5,000 times higher dose (Meire, 1987), and there are no stan- The second recognised effect is cavitation, where the small dards to ensure that the lowest dose is used. Because of the com- ockets of gas which exist within mam- plexity of machines, it is difficult even malian tissue vibrate and then collapse. to quantify the dose given in each In this situation: "...temperatures of examination (Taylor, 1990). In many thousands of degrees Celsius in A further problem with Australia, training is voluntary, even for the gas create a wide range of chemical . 1 obstetricians, and the skill and experi- roducts, some of which are potentially studying ultrasound Ss effects ence of operators varies widely. toxic. These violent processes may be 1 A summary of the safety of ultra- roduced by micro-second pulses of the Is the huge fel he of output, sound in human studies, published in kind which are used in medical diagno- or dose, possible from May 2002 in the prestigious US journal sis..." (American Inst. of Ultrasound 1 I Epidemiology, concluded: "...there Medicine Bioeffects Report, 1988). The a single machine. may be a relation between prenatal ultrasound exposure and adverse out- uman tissue is unknown. come. Some of the reported effects A number of studies have suggeste include growth restriction, delayed that these effects are of real concern in living tissues. The first speech, dyslexia, and non-right-handedness associated with ultra- study suggesting problems was a study on cells grown in the lab. sound exposure. Continued research is needed to evaluate the Cell abnormalities caused by exposure to ultrasound were seen to _ potential adverse effects of ultrasound exposure during pregnan- ersist for several generations (Liebeskind, 1979). Another study cy. These studies should measure the acoustic output, exposure showed that, in newborn rats (who are at a similar stage of brain time, number of exposures per subject, and the timing during the significance of cavitation effects in development to humans at four to five months in utero), ultra- pregnancy when exposure(s) occurred" (Marinac-Dabic, 2002). sound can damage the myelin that covers nerves (Ellisman et al., The UK consumer organisation AIMS (Association for 1987), indicating that the nervous system may be particularly sus- Improvements in the Maternity Services) has produced a booklet, ceptible to damage from this technology. "Ultrasound Unsound?", originally published in 1993 and recently A 1999 animal study by Brennan and colleagues, reported in updated. This very comprehensive publication, which I highly New Scientist (12 June 1999), showed that exposing mice to recommend, includes a form that pregnant women undergoing dosages typical of obstetric ultrasound caused a 22% reduction in ultrasound can ask their carers to fill out. You can make your the rate of cell division and a doubling of the rate of aptosis, or | own form based on the information as below, or obtain the book- programmed cell death, in the cells of the small intestine. let at website http://www. birthinternational.com.au. Mole (1986) comments: "If exposure to ultrasound...causes death of cells, then the practice of ultrasonic imaging at 16 to 18 | WOMEN'S EXPERIENCES WITH ULTRASOUND weeks will cause loss of neurones [brain cells] with little prospect Women have not been consulted at any stage in the develop- of replacement of lost cells... The vulnerability is not for malfor- ment of this technology, and their experiences and wishes are pre- mation but for maldevelopment, leading to mental impairment — sumed to coincide with, or be less important than, the medical caused by overall reduction in the number of functioning neu- information that ultrasound provides. For example, supporters of rones in the future cerebral hemispheres." RPU presume that early diagnosis and/or termination is beneficial Studies on humans exposed to ultrasound have shown that _ to the affected woman and her family. possible adverse effects include premature ovulation (Testart, However, the discovery of a major abnormality on RPU can 1982), preterm labour or miscarriage (Lorenz, 1990; Saari- lead to very difficult decision-making. Some women who agree Kemppainen, 1990), low birth weight (Newnham, 1993; Geerts, to have an ultrasound are unaware that they may get information 1996), poorer condition at birth (Thacker, 1985; Newnham, about their baby that they do not want, as they would not contem- 1991), perinatal death (Davies, 1992), dyslexia (Stark, 1984), plate a termination. Other women can feel pressured to have a delayed speech development (Campbell, 1993), and less right- termination, or at the least feel some emotional distancing from handedness (Salvesen, 1993; Kieler, 1998a; Salvesen, 1999). their "abnormal" baby (Brookes, 1994-95). Non-right-handedness is, in other circumstances, seen as a marker Furthermore, there is no evidence that women who have chosen of damage to the developing brain (Odent, 1998). One Australian termination are, in the long term, psychologically better off than A further problem with studying ultrasound's effects is the huge range of output, or dose, possible from a single machine. WOMEN'S EXPERIENCES WITH ULTRASOUND Women have not been consulted at any stage in the develop- ment of this technology, and their experiences and wishes are pre- sumed to coincide with, or be less important than, the medical information that ultrasound provides. For example, supporters of RPU presume that early diagnosis and/or termination is beneficial to the affected woman and her family. However, the discovery of a major abnormality on RPU can lead to very difficult decision-making. Some women who agree to have an ultrasound are unaware that they may get information about their baby that they do not want, as they would not contem- plate a termination. Other women can feel pressured to have a termination, or at the least feel some emotional distancing from their "abnormal" baby (Brookes, 1994-95). Furthermore, there is no evidence that women who have chosen termination are, in the long term, psychologically better off than NEXUS ¢ 19 OCTOBER — NOVEMBER 2002 www.nexusmagazine.com