LONDON ― Children with autism spectrum disorder (ASD) may have more rapidly growing brains and bodies at the beginning of the second trimester than children without the disorder, new research suggests.
A small retrospective study examining fetal anomaly ultrasound scans showed that the children who went on to develop ASD had significantly greater head and abdominal circumference and cerebellar diameter at around 20 weeks’ gestation than did their healthy peers.
“This gave us a small window into the fetal development of these children, and it looked like something about autism was happening at that 20-week mark,” lead author Lois Salter, a medical student at the University of Edinburgh in Scotland, told Medscape Medical News.
“If we could explore this further, it might help with diagnosing earlier and treating earlier. It just opens a whole range of possibilities if autism is detectable this early on,” said Salter.
The results were presented here at the International Congress of the Royal College of Psychiatrists (RCPsych) 2014.
Early Detection
“Previous research suggests that autism may be detectable from infancy,” write the investigators, adding that they wanted to evaluate whether it could be detectable even earlier.
Fetal anomaly scans have been routinely performed since December 2008 in the Lothians, a region of the Scottish Lowlands.
The researchers sought to examine these scans for 40 children who were later diagnosed with ASD and for 120 children who did not develop the disorder (healthy control participants). Fetal data from the scans for head circumference, cerebellar diameter, femur length, abdominal circumference, and ventricular atrial width were assessed.
In addition, researchers controlled for maternal age and other demographic factors.
Results showed a “significant interaction of group” between head circumference, cerebellar diameter, femur length, and abdominal circumference (all, P < .05), suggesting that the children who had autism were growing at a faster rate at the 18- to 24-week gestational point than were the healthy control individuals. There were no significant between-group differences in ventricular atrial width. "These results suggest that children with autism grow at a different rate to controls in the beginning of the second trimester; notably, both their brains and bodies appear to grow faster at this stage," write the researchers. "Autism may thus be detectable much earlier in development, allowing for targeted early detection and treatment of the condition," they add. Salter noted that this could also lead to earlier and better education. "We're not waiting for symptoms to show up at age 3 or 4, when you've lost years of potential education for parents and for children," she said. She reported that the investigative team hopes to keep following up with these data as more children are diagnosed with ASD and more scans are added into the system. "It would also be great to look into a bit of a wider window of the gestation, but that would have to be prospective, possibly scanning high-risk mothers throughout their pregnancy," said Salter. For now, she is excited by these results. "We didn't really have a clue what to expect," she said. "Postnatal data about brain size in autism is really mixed, with nothing massively conclusive. So to find something in utero is great." "Furthers Our Understanding" Bernice Knight, MBChB, MRCPsych, academic clinical lecturer in intellectual disability psychiatry at the University of Bristol, in the United Kingdom, and executive committee member of the Faculty of the Psychiatry of Learning Disability for the Royal College of Psychiatrists, told Medscape Medical News that these findings dovetail nicely with a study she and her colleagues recently completed that looked at traits that might predict ASD later in childhood. Dr. Knight, who was not involved with the current study, noted that the complementary findings were interesting. In addition, she said that these new results have the potential to be very helpful to clinicians and others. "There is so much that we don't understand about autism and about autism spectrum disorder. And given that it's clearly a neurodevelopmental disorder, I think looking at those early stages of development are going to be fundamental to improving our understanding," she said. "So concentrating research into that area is likely to be fruitful and helpful, ultimately, for patients."