in vitro studies shows that ultrasound has produced cell damage and changes in DNA. The most widely quoted studies are those of radiologist Doreen Liebeskind at New York’s Albert Einstein College of Medicine. After exposing cells in suspension to low-intensity pulsed ultrasound for 30 seconds, she observed changes in cell appearances and motility, DNA, abnormal cell growth and chromosomes, some of which were passed on to succeeding cell generations. In a documentary made of Dr Liebeskind’s results, the film showed normal cells with rounded edges more or less moving in tandem. After exposure to ultrasound, the cells became ‘frenetic and distorted’, and entangled with one another, wrote Doris Haire, president of the American Foundation of Maternal and Child Health, one of America’s best-briefed and most vociferous critics of routine ultrasound use.25 Robert Bases, chief of Radiology at Albert Einstein College, reviewing what he termed the ‘bewildering array of ultrasound bioeffects described in over 700 publications since 1950’, said Dr Liebeskind’s results had been confirmed by four independent laboratories.26
Dr Liebeskind herself theorizes that these cell changes may affect the developing brain. ‘There may be some subtle or delayed effect on neuron interconnection or some type of effect that is not readily apparent until later,’ she says.27 Dr Liebeskind and others believe the in vitro studies can help to pinpoint the subtle effects on humans that epidemiologists should be looking for. ‘I’d look for possible behavioural changes – in reflexes, IQ, attention span,’ she wrote.28
The International Childbirth Education Association (ICEA) has maintained that ultrasound is most likely to affect development (behavioural and neurological), blood cells, the immune system and a child’s genetic make-up – a view that has been borne out by the recent evidence about weight and development in exposed children.29 Ultrasound has also been shown to affect many parts of the mother’s body. A British study demonstrated that ovarian ultrasound can trigger premature ovulation in the mother.30 There also have been published reports showing ultrasound’s potential to damage maternal erythrocytes (mature red blood cells) and raise chorionic gonadotropin levels (the hormone which helps to maintain the pregnancy).31 Again, we’re not really sure what this means, and whether a woman is more likely to miscarry after ultrasound exposure.
Despite the assurances of the UK’s Royal College of Obstetricians and Gynaecologists, every major American government agency has insisted that ultrasound not be used routinely on pregnant women. The FDA, the American Medical Association, the US National Institute of Child Health and Human Development, a top epidemiologist for the Centers for Disease Control and Prevention, the ACOG and the Bureau of Radiological Health have all cautioned doctors to use ultrasound only when indicated (say, to investigate unexplained vaginal bleeding) – a caution that has got thrown to the winds. They also specify that there is still no research proving this diagnostic test is safe. The Bureau of Radiological Health, for instance, has stated:‘Although the body of current evidence does not indicate that diagnostic ultrasound represents an acute risk to human health, it is insufficient to justify an unqualified acceptance of safety.’32
Besides the safety issue, there are considerable questions about accuracy. There is a significant chance that your scan will indicate a problem when there isn’t one, or fail to pick up a problem actually there. One study found a ‘high rate’ of false-positives; 17 per cent of the pregnant women scanned were shown to have small-for-dates babies, when only 6 per cent actually did – an error rate of nearly one out of three.33 Another study from Harvard showed that among 3,100 scans, 18 babies were erroneously labelled abnormal, and 17 foetuses with problems were missed.34
Yet a third Swiss study pooling the results of all ultrasound studies concluded that 2.4 per 1,000 women will be given a false diagnosis of a malformed foetus. This high error rate has chilling repercussions for families who decide to opt for late-term abortions after a scan shows that their child has spina bifida.35 In fact, the Swiss researchers concluded that the negligible benefits of ultrasound scanning (which don’t improve the outcome of pregnancy) aren’t worth exposing pregnant women to the ‘risk of false diagnosis’ of malformations.
In one of the largest studies on ultrasound to date (33,000 babies), ultrasound picked up only about half of the 725 babies with birth defects. Some 175 foetuses were given a false-positive result – labelled abnormal when they were healthy.36 A Swedish study found that ultrasound picked up only a third of babies born with serious defects37 and, in another study, only a third of growth-retarded babies were correctedly diagnosed before birth. Some 2 per cent were wrongly identified as such, even though their mothers had had nearly five scans apiece.38
False-positives have increased 12-fold as ultrasound is increasingly used in an attempt to pick up subtle defects or conditions in late pregnancy.39 This technology even wildly overdiagnoses placenta praevia (potentially fatal low-lying placenta in late pregnancy), one of its main indications; in one study, 250 women were identified as having the condition when it was only actually present in four.40
At one point, the British press was filled with stories of women who may have aborted healthy babies due to inaccurate scans. In one, Jacqui James of Brierley Hill in the West Midlands, a 24-year-old mother of two, was told scans done at Birmingham Maternity Hospital during her 27th week of pregnancy showed that her third baby was not growing properly and likely to have brain damage. After a family discussion, she decided she had no choice but to have an abortion. Because she was more than six months pregnant, the ‘abortion’ was done by caesarean section. However, the baby girl, which survived the operation for 45 minutes, was later found to be perfectly healthy.41
THE NEW DOWN’S TEST
Ultrasound scans are now used to predict Down’s syndrome. A nuchal scan measures the depth of the dark fluid-filled space at the back of the baby’s neck at 10–13 weeks of pregnancy. If the space is thicker than usual, your baby may be at risk of Down’s.
However, the nuchal scan throws up false-positives, signalling Down’s when it isn’t. For instance, in a study of more than 96,000 pregnancies, the scan was only 80 per cent accurate, even among women at high risk of a Down’s baby. According to one large-scale study, 87,000 women would have to be scanned to find one accurate diagnosis.42 But of course the biggest risk of all in false-positives is that they open up the door to more invasive tests such as amniocentesis, which carry their own substantial risks. Ultimately, more healthy babies could be lost through amniocentesis than Down’s babies be detected.
Considering its extremely poor track record of accuracy, ultrasound may not even be useful very late in pregnancy to help confirm the position of the baby. The only rationale for scanning most uneventful pregnancies is to satisfy our curiosity, to try to get a little closer to the mystery of life.
FOETAL MONITORING DURING LABOUR
When
