“I am not saying they are not safe. None of the professional bodies ever say ultrasound is unsafe, but I would say, if there’s a medical reason to have an ultrasound, have it, but if it’s purely for curiosity, don’t.”
Ms Karen Pollard, lecturer with the School of Clinical Sciences at CSU's Wagga Wagga Campus, talking about the issues surrounding the use of routine or screening scans in pregnancy. Her public lecture, Baby Scans: Is Ultrasound Sound? will be delivered tomorrow night (Thursday 21 September) at the Bathurst Civic Centre. She says she will be presenting a balanced view weighing up the benefits of the non-diagnostic ultrasound versus the medical application.
“The American Institute of Ultrasound in Medicine (AIUM) official statement says ‘widespread clinical use over 25 years has not established any adverse effect arising from exposure to diagnostic ultrasound’. And that was re-issued in 1997. But most of the studies were done in the 1980s”, says Ms Pollard.
“Even some of the studies that were done in the last 10 years are really not relevant to today’s exposure. The equipment we use now has far greater exposure intensity than earlier scans, and we are using different techniques,” she added.
“What we do know about intensities at that level is if you were to ultrasound a cyst, you may see acoustic streaming, that is, the fluid in the cyst starts to move around. If it can do that to the fluid inside a cyst at relatively short exposure times, what is it doing to a 12-week foetus which is at a stage of development where cell division is happening and the organs are forming? I have some concerns.”
According to Ms Pollard, ultrasound scans used to be performed at about 18 to 20 weeks through the mother’s abdomen. Now it has become routine to have a transvaginal ultrasound at 12 weeks. “So the ultrasound probe is right up against the cervix, right next to the foetus.”
Ms Pollard says current studies are few and far between, partly because most pregnant women have scans. “It has become a routine part of the pregnancy. If someone asks, is it safe? The GP may say, ‘yes’, whereas the sonographer will say, ‘well we think so, as far as we know’.
“A ten year study out of Western Australia showed that babies who were scanned a lot had significant growth retardation, but that’s probably why they were being scanned, because there were worries about those particular baby’s growth rates. Were they smaller because of the ultrasound? We just don’t know.
“But the scans they are doing today versus ten years ago are just so powerful. The equipment they use now is phenomenal. You can have an image taken these days which is just beautiful, it’s not like the blur of old.”