Paolo Rossi Castelli 5 May 2022 18 min read

Are the symptoms of autism already evident during pregnancy?

Two U.S. studies reveal that the insula and amygdala in the brain are enlarged in the early months of gestation in autistic children, but further research is needed.

The complicated mosaic that explains (or, at least, attempts to explain) autism now has a couple more pieces that support the currently prevalent idea that this complex condition originates much earlier than previously thought. Autism is a neurodevelopmental disorder that can cause issues with communication, cognitive function, awareness and emotional perception.

In particular, according to a study recently presented by neonatologists and neurologists at Harvard University (USA), abnormalities arise during pregnancy, while according to another study published a few days earlier, it is possible to see that something is not right from the very first months of life and not, as previously thought, only after 18 months.

Two enlarged areas of the brain are among the symptoms of autism
The Harvard University research was presented at the American Association for Anatomy meeting on experimental biology. The US scientists explained what they found by examining MRI scans of 39 foetuses in the womb, with an average gestational age of 25 weeks, at the Boston Children's Hospital. Nine of these children were diagnosed as autistic in the following months/years.

By comparing the images with those of a sophisticated digital archive charting the development of the brain from the earliest days of foetal life, the researchers highlighted a number of unique features in autistic babies compared to others: firstly, an enlarged area called the insula lobe (seen as early as 25 weeks) which is linked to the processing of sensory stimuli, socialisation and decision-making processes, which appeared larger than that of all other foetuses.

Another focus on a second area
This confirms a number of observations also made on adults with autism, in whom the same area of the cortex is enlarged.

MRI scans also showed an increase in volume in the amygdala, another area of located deep inside the brain responsible, among other things, for processing emotions and interpreting the facial expressions of others. This hypertrophism, as it is known in technical terms, had already been discovered a few years ago in school age autistic children. But that is not all…

An enlarged amygdala is the ideal basis of a second study, published in the American Journal of Psychiatry by researchers at the University of North Carolina in Chapel Hill. Over a thousand MRI scans of 408 new-borns were analysed, 270 of which were at risk because they were siblings of autistic children (58 of whom went on to develop the condition). Researchers were thus able to demonstrate that the amygdala was normal in babies destined to become autistic up to 6 months, but between 6 and 12 months they began to see enlargement, before the clinical manifestations of the condition.

The amygdala continued to grow up to 12-24 months, the age at which the first interpersonal difficulties usually appear. Moreover, researchers found that the faster the rate of growth, the worse the manifestations of condition, which generally has different levels of severity (hence the term autism spectrum disorders). The issues were even more evident around the age of two, in aspects related to sociability, the faster the amygdala grew from the first year of age. Abnormal development of the amygdala may therefore start in the mother's womb and continue silently until the age of two, at which point the damage is already such that the normal (cognitive) development of the infant is affected.

Studies on new advance treatments
This information is important, not only because it sheds new light on autism spectrum disorders (which are still largely shrouded in mystery), and therefore makes it easier to develop innovative possible treatments, but also (and above all) because it could enable early diagnosis – perhaps during pregnancy or in the very first months of life. Targeted action could slow down the progression of autism (especially regarding language and cognitive abilities) and thus prevent the situation from becoming irreversible.


Seguici su Facebook     New call-to-action    Seguici su LinkedIn


Paolo Rossi Castelli

Journalist since 1983, Paolo has been dealing with scientific divulgation for years, especially in the fields of medicine and biology. He is the creator of Sportello Cancro, the site created by on oncology in collaboration with the Umberto Veronesi Foundation. He collaborated with the pages of the Science of Corriere della Sera for several years. He is the founder and director of PRC-Comunicare la scienza.