Although women are now routinely offered several ultrasound scans during a pregnancy, costing health services worldwide millions of pounds every year, its safety has never been tested. This assumption of safety has led to:

• researchers who are studying foetal behaviour reassuring women volunteering to take part in their trials that exposures of up to an hour and a half are safe

• commercial companies offering parents lengthy ‘videos’ of their baby moving inside the womb. (The US Food and Drink Administration (FDA) warns that ultrasound cannot be considered harmless, even at low levels, and is considering regulatory action against these companies)

• companies being granted safety licenses to offer parents- to-be hand-held Doppler ultrasound devices with which, theoretically, they could expose their babies to hours of ultrasound every day

Several trials suggest that Governments should be more concerned, e.g.:

• When women at risk of giving birth preterm were examined once a week to determine the state of their cervix, just over half (52%) of those who were examined using ultrasound went on to have a preterm birth compared to a quarter (25%) of those given a manual pelvic examination.
  Ultrasound scanning gave no benefit over manual examination [1]

• When 1,246 UK women were given a monthly Doppler ultrasound scan of their umbilical and uterine arteries from the 19th to the 32nd week of pregnancy, seventeen of their babies died at or around the time of birth, as opposed to only seven in the 1,229-strong unDopplered control group. The Doppler scanning had only identified a possible problem in one of the babies [2]

Ed.- (i) AIMS Journal’s Jean Robinson is concerned that no research has ever been done on the effects of:

• exposing even younger foetuses to ultrasound, an increasingly common practice

• submitting foetuses to exposures of an hour or more, as in the commercial applications described above

She also points out that:

• because ultrasound is now almost universally used, it has become almost impossible to assemble a control group of completely unexposed children. Only degrees of exposure can now be compared

• the claim that ultrasound encourages bonding between mother and child has also never been demonstrated scientifically

(ii) Other studies, however, suggest that ultrasound is more efficient than manual pelvic examination at detecting major malformations and twins early. [3]

Having one or more ultrasound scan to see your baby in the womb has become almost the norm. Although there has never been any significant research to prove it, the practice is assumed totally safe by doctors and parents-to-be alike. In fact, the opposite is true.

Three randomised controlled trials of Doppler Sound, the powerful form of ultrasound now used in most hospitals, have found an up to fourfold increase in perinatal (just before or after birth) deaths. [1] One large study found 20 miscarriages in the group given ultrasound scans, but none in the group which was not. [2] Another reported a doubling of pre-term labour in the scanned group. [3] Another linked ultrasound scanning to retardation of the baby's growth in the womb. [4]

Animal-based studies suggest that there may be subtler effects which have, to date, not been measured in humans. Monkeys repeatedly exposed to ultrasound showed clear behavioural problems, such as social withdrawal. Another study using monkeys found evidence of low body weight and poor muscle tone.

Experiments with guinea pigs showed that it could raise the temperature of brain tissue near bone by as much as 5.1°C. [5] If the same occurs in human babies at the time the developing brain is at its most vulnerable (16 weeks old, when ultrasound scanning tends to be carried out), it is possible that vital cells could be damaged or destroyed with little possibility of replacement. This could lead to long-term neurological damage. [6] Changes in brain development sometimes lead to lefthandedness. [7] Not a problem in itself, but lefthandedness is linked to an increased risk of dyslexia, [8] learning difficulties [9] and speech delay. [10]

The argument for ultrasound scanning revolves around its ability to detect abnormalities early enough to abort. Firstly, several studies have shown that ultrasound does not improve outcomes for babies overall, and that there is no medical reason to propose a scan in 80% of cases. Secondly, ultrasound can only detect a handful of the 5000+ potential chromosomal abnormalities. It is most successful at detecting Down's syndrome, picking up 80% of cases, but even here can diagnose Down's syndrome when it isn't actually present. Scanning can pick up `things that shouldn't be there' - resulting, again, in the abortion of healthy foetuses - when that `thing' often disappears during the pregnancy. Parents who decide not to abort are put through months of unnecessary worry. In one instance at a hospital in Cardiff (Wales), scans detected `dead' babies which were subsequently found to be alive just before the induced miscarriage was to be performed.

Finally, scans can pick up abnormalities about which nothing can be done.

New research suggests that ultrasound tests may affect babies’ brains. Looking back at 2161 babies born 1979-81 Norwegian researchers found that those who had been exposed to ultrasound were 30% more likely to be left-handed. This could have happened by chance but they believe it may indicate “a sensitive index of subtle changes in the development of the brain”.
(5135) Salvesen,KA et al. British Medical Journal 1993;307(6897):159-64

Ultrasound scans linked to brain damage in babies
A third study has linked lefthandedness to ultrasound scanning, suggesting that it has caused genetic damage in the brain. In this case 7000 men whose mothers had ultrasound scans in the ’70s were compared to 170,000 men whose mothers did not. There was a significant increased rate of lefthandedness in the 7,000 men who had been scanned when in the womb and, critically, an even higher increase in those born after 1975, when doctors introduced a routine second scan. Lefthandedness is linked to an increased risk of a range of conditions, e.g.learning difficulties, dyslexia and epilepsy. The study was conducted on men because male babies’ brains continue to develop later than female babies’ brains, making them more susceptible to damage from external factors.

In Britain, lefthanded people now form 11% of the population, compared to just 5% in the 1920s. The researchers have estimated that only a fifth of this doubling can be accounted for by a relaxation on the old practice of suppressing lefthandedness.

(8663) Kieler,H et al. Epidemiology 2001;12(6):618-23
Courtesy of Robert Matthews. Sunday Telegraph 9.12.2001

No link with childhood leukaemia
A large case-controlled study from Sweden was unable to show any link between the use of ultrasound examination of babies in the womb and childhood leukaemia. In the preamble to the research description, however, the authors remind us that other studies have shown that ultrasound can cause membrane changes which might affect the embryo’s development as well as postnatal development, and that ultrasound has been associated with lefthandedness.

(6146) Naumburg,E et al. British Medical Journal 29.1.00 p282

Ultrasound - small babies catch up
In 1993 Australian research [1] found some evidence that foetuses exposed to five sessions of ultrasound imaging and continuous-wave Doppler flow studies between the eighteenth and thirty-eighth week of pregnancy tended to be born smaller and shorter than babies given a single ultrasound scan in the eighteenth week.

Some good news
The team followed the babies’ progress for the next eight years. By the time the babies were a year old, there were no significant differences in size. When the children underwent standard tests of childhood speech, language, behaviour and neurological development at ages two, three, five and eight, it suggested that the children’s neurological development had been normal as well.

Ed.- (i) These findings come as a relief, but the fact that the repeated ultrasound or Doppler scans reduced the foetus’ growth is still cause for alarm. Doppler scans are not the same as ultrasound scans. They are used to measure blood flow in the foetus’s arteries and expose the foetus to larger doses of ultrasound.

AIMS Journal’s Jean Robinson commented as follows:

The Doppler and ultrasound imaging machines used in the original 1993 trial were weaker than those used these days. No research on the safety of today’s machinery has been carried out

The researchers are still concerned by the apparent link between boy’s exposure to ultrasound and an increased likelihood of being left-handed.{2] They intended to examine this issue when the children were ten