Seeing those first grainy pictures of bub has to be one of absolute highlights of pregnancy. You get your first hint of what the little person growing inside you might be like, in looks and perhaps even in personality. Not to mention the excitement of finally being able to share your pregnancy joy with others in a really tangible way.
Most women have the standard 12 and 20-week scans, perhaps one or two more if there are queries on mum or bub’s health. Others have an ultrasound every time they go for a prenatal check-up. Parents can also pay to have private sonographers conduct ultrasounds for the sole purpose of getting another peek at baby.
In the US, the average number of pregnancy scans undergone by women has risen sharply – up 92 per cent to 5.2 per delivery in the 10 years to 2014, says the Wall Street Journal.
Ultrasounds bounce sound waves off the foetus, picking up the reflections and converting them into pictures. They help give a more accurate estimate of conception and due dates, and can pick up abnormalities and complications. They are considered crucial in high-risk pregnancies. The WSJ says research has found they can even help mother-baby bonding, including persuading some pregnant women to quit smoking.
But medical experts have called for just one or two ultrasounds in the 80 per cent of pregnancies that are low-risk and uncomplicated – saying there is no justification for frequent scans in those women.
A joint statement from organisations including the American College of Obstetricians and Gynecologists says scans should be used “only when clinically indicated, for the shortest amount of time and with the lowest level of acoustic energy compatible with an accurate diagnosis”.
The WSJ says pregnancy ultrasounds have never been shown to cause harm to unborn babies, but nearly all research on their safety was undertaken before 1992. Back then, scans produced about one-eighth the acoustic energy they are allowed to emit today, and foetal ultrasounds were much less frequent.
It reports there are “some unknowns” about the long-term effects of modern equipment, and whether ultrasound technicians pay enough attention to safety gauges. It says the US Food and Drug Administration warned last December that ultrasound can heat tissues and sometimes create small bubbles in them, the effects of which are also unknown. Importantly, experts also believe that ultrasounds can cause unnecessary concern, including overestimating the size of the baby and therefore leading to unnecessary C-sections.
World Federation for Ultrasound in Medicine and Biology safety committee chair Jacques Abramowicz says many doctors are of the view that ultrasound is safe because it emits no carcinogenic radiation, and warning women about potential negatives could scare women off having a procedure that can be of great medical benefit.
But other doctors, including Journal of Diagnostic Medical Sonography editor Dr Phillip J Bendick, say mums-to-be should be explicitly told they only need one or two scans in average low-risk pregnancies. “The public needs to be made aware that if you’re pregnant, you don’t drink alcohol, you don’t smoke and you don’t need to have an ultrasound at every doctor’s visit,” he says.