A new study may be stoking unnecessary fears among pregnant women. Researchers in the U.S. looked at boys who were already diagnosed with autism spectrum disorder and tried to figure out if the number of ultrasounds that the mom had undergone during her pregnancy led to more severe autistic symptoms later on. The study seemed to indicate that it did, but you have to be careful interpreting this data.
These were children who were already genetically predisposed to autism and had developed the disorder. Furthermore, this is a recall study: the moms were asked to remember how many ultrasounds they had. No one went back to check the medical files for accuracy of recall and we all know how faulty memory can sometimes be. We also don’t know why these ultrasounds were being done. Perhaps there were problems with the pregnancy that both led to the increased severity of the autism and also led to more ultrasounds having to be done.
This study doesn’t prove ultrasound causes autism. What it does, though, is reinforce the fact that as with any medical intervention we need to do it only when it’s medically indicated.
A normal, uncomplicated pregnancy needs on average two ultrasounds — one at around 12 weeks and one at around 20 weeks. If, however, there are complications, ultrasound is one of the safest ways we have to monitor the pregnancy.
The key message in this study is not that ultrasound is dangerous but rather than we need to limit it — as we need to limit any intervention — to when it’s truly useful. The truth is that the average number of ultrasounds being done — even in normal, uncomplicated pregnancies — seems to be on the rise. One study in the U.S. showed a 92 per cent increase. That’s the key message.
So please don’t avoid an ultrasound because of the fear that it might cause autism if you and your doctor are dealing with a medical issue during the pregnancy. But don’t do it just to have a picture of the baby to share on Facebook.
Dr. Mitch Shulman is an Assistant Professor, Dept. of Surgery, McGill Medical School and an Attending Physician, Emergency Department, McGill University Health Centre. He’s also the CJAD AM 800 Medical Consultant.