Ultrasound: Weighing the Propaganda Against the Facts
It is ironic that women who have had previous miscarriages often have additional ultrasound examinations in order to "reassure" them that their baby is developing properly. Few are told of the risks of miscarriage or premature labour or birth.
Obstetricians in Michigan (Lorenz et al., 1990) studied fifty-seven women who were at risk of giving birth prematurely. Half were given a weekly ultrasound examination; the rest had pelvic examinations. Preterm labour was more than doubled in the ultrasound group–52 percent–compared with 25 percent in the controls. Although the numbers were small the difference was unlikely to have emerged by chance.
A large randomised controlled trial from Helsinki (Saari-Kemppainen et al., 1990) randomly divided over 9,000 women into a group who were scanned at sixteen to twenty weeks compared with those who were not. It revealed twenty miscarriages after sixteen to twenty weeks in the screened group and none in the controls.
A later study in London (Davies et al., 1993) randomised 2,475 women to routine Doppler ultrasound examination of the umbilical and uterine arteries at nineteen to twenty-two weeks and thirty-two weeks compared with women who received standard care without Doppler ultrasound. There were sixteen perinatal deaths of normally formed infants in the Doppler group compared with four in the standard care group.
It is not only pregnant patients who are at risk, however. Physiotherapists use ultrasound to treat a number of conditions. A study done in Helsinki (Taskinen et al., 1990) found that if the physiotherapist was pregnant, handling ultrasound equipment for at least twenty hours a week significantly increased the risk of spontaneous abortion. Also, the risk of spontaneous abortions occurring after the tenth week was significantly increased for deep heat therapies given for more than five hours a week and ultrasound more than ten hours a week.
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When ultrasound was first developed researchers suggested that "the possibility of hazard should be kept under constant review" (Donald, 1980), and they said that it would never be used on babies under three months. However, as soon as vaginal probe ultrasound was developed, which could get good pictures in early pregnancies (and get nearer to the baby giving it a bigger dose), this initial caution was ignored.
Research by Lieberskind revealed "the persistence of abnormal behaviour . . . in cells exposed to a single dose diagnostic ultrasound ten generations after insonation." She concluded, "If germ cells were . . . involved, the effects might not become apparent until the next generation" (Lieberskind, 1979). When asked what problems should be looked for in human studies, she suggested: "Subtle ones. I’d look for possible behavioural changes, in reflexes, IQ, attention span" (Bolsen, 1982).
Because ultrasound has been developed rapidly without proper evaluation it is extremely difficult to prove that ultrasound exposure causes subtle effects. After all, it took over ten years to prove that the gross abnormalities found in some newborn babies were caused by thalidomide. However, there are a number of ultrasound studies which raise serious questions that still have to be addressed.
The first evidence we saw of possible damage to humans came in 1984 when American obstetricians published a follow-up study of children, aged seven to twelve years born in three different hospitals in Florida and Denver, who had been exposed to ultrasound in the womb (Stark et al., 1984). Compared with a control group of children who had not been exposed they were more likely to have dyslexia and to have been admitted to hospital during their childhood, but no other differences were found.
In 1993 a study in Calgary, Alberta which examined the antenatal records of seventy-two children with delayed speech of unknown cause were compared with those of 142 controls who were similar in sex, date of birth and birth order within the family. The children were similar in social class, birthweight and length of pregnancy. The children with speech problems were twice as likely as controls to have been exposed to ultrasound in the womb. Sixty-one percent of cases and only 37 percent of controls had had at least one exposure.
A Norwegian study (Salvesen, 1993) showed an increase in left handedness, but no increase in dyslexia. While the increase in left handedness was not large, it does suggest that ultrasound has an effect on the development of the brain. It should be noted, however, that the scanners used in this study emitted very low doses of ultrasound–lower than exposures from many machines nowadays–the women had only two exposures, and it was real time, not Doppler, a more powerful form of ultrasound.
Assessing the risks "Present day ultrasonic diagnostic machines use such small levels of energy that they would appear to be safe, but the possibility must never be lost sight of that there may be safety threshold levels possibly different for different tissues, and that with the development of more powerful and sophisticated apparatus these may yet be transgressed" (Donald, 1979).
Donald’s foresight was remarkable. The machines in use today are far more powerful than the machines used a decade or more ago, and new variants are being developed all the time.
(I prijatelje koji su nam darovali gotovo svu opremu za bebu, pa ćemo uštediti dosta love i akonto toga razmišljamo o Podobniku).
Odgovori s citatom
Manuela. prvotno napisa
Zar je vani drugačije? Pa truli kapitalizam vlada svijetom... što je tu neobično? 
) dok nije dobio službenu potvrdu liječnika. Ovo pivo je simbolično, može i gemišt. 
Sigurno ima i toga, ali nikako nije pravilo.
