Ultrasound scans: cause for concern.

This article has appeared in Nexus magazine, Oct-Nov 2002.

When I was pregnant with my first baby in 1990, I decided against having a scan. This was a rather unusual decision, as my partner and I are both doctors and had even done pregnancy scans ourselves--rather ineptly, but sometimes usefully--while training in GP Obstetrics a few years earlier.

What influenced me the most was my feeling that I would lose something important as a mother if I allowed someone to test my baby. I knew that if a minor or uncertain problem showed up, which is not uncommon, I would be obliged to return again and again, and that after a while, it would feel as if my baby belonged to the system, not to me.

In the years since, I have had three more unscanned babies and have read many articles and research papers about ultrasound. Nothing I have read has made me reconsider my decision. Although ultrasound may sometimes be useful when specific problems are suspected, my conclusion is that it is at best ineffective and at worse dangerous when used as a "screening tool" for every pregnant woman and her baby.

Ultrasound past and present

Ultrasound was developed during WWII to detect enemy submarines, and was subsequently used in the steel industry. In July 1955 Glasgow surgeon Ian Donald borrowed an industrial machine and, using beefsteaks as controls, began to experiment with abdominal tumours that he had removed from his patients. He discovered that different tissues gave different patterns of "echo" leading him to realise that ultrasound offered a revolutionary way to look into the previously mysterious world of the growing baby (Wagner 1995).

This new technology spread rapidly into clinical obstetrics. Commercial machines became available in 1963 (De Crespigny 1996), and by the late 1970s ultrasound had become a routine part of obstetric care (Oakley 1986). Today, ultrasound is seen as safe and effective and scanning has become a rite of passage for pregnant women in developed countries. Here in Australia, it is estimated that 99 percent of babies are scanned at least once in pregnancy--mostly as a routine prenatal ultrasound (RPU) at four to five months.

However, there is growing concern as to its safety and usefulness. UK consumer activist Beverley Beech has called RPU "the biggest uncontrolled experiment in history" (Beech 1993), and the Cochrane Collaborative Database--the top scientific authority in medicine--concludes that "... no clear benefit in terms of a substantive outcome measure like perinatal mortality [number of babies dying around the time of birth] can yet be discerned to result from the routine use of ultrasound." (Neilson 1999).

This seems a very poor reward for the huge costs involved. Between 1997 and 1998, for example, $39 million was paid by the Australian government for pregnancy scans--an enormous expense compared to $54 million for all other obstetric Medicare costs. This figure does not include the additional costs paid by the woman herself.

In 1987, UK radiologist H.D. Meire, who had been performing pregnancy scans for 20 years, commented, "The casual observer might be forgiven for wondering why the medical profession is now involved in the wholesale examination of pregnant patients with machines emanating vastly different powers of energy which is not proven to be harmless to obtain information which is not proven to be of any clinical value by operators who are not certified as competent to perform the operations." (Meire 1987) The situation today is unchanged, on every count.

In the US, it is estimated that 60 to 70 percent of pregnant women have an ultrasound scan (ACOG 1993) at a cost of approximately $300 per procedure, adding up to between $70 and $80 billion spent on ultrasound per year. This is despite an ACOG recommendation against routine ultrasound.

What is Ultrasound? The term "ultrasound" refers to the ultra-high frequency sound waves used for diagnostic scanning: these waves vibrate at 10 to 20 million cycles per second, compared to 10 to 20 thousand cycles per second for audible sound (De Crespigny 1996). …