London - Boys who develop autism are exposed to higher levels of steroid hormones in the womb than those who don’t develop the condition, according to a study that further dispels the role of vaccines.
Prenatal levels of substances such as testosterone, progesterone and cortisol were greater, on average, in boys who were later diagnosed with autism, scientists at the University of Cambridge and the Statens Serum Institute in Copenhagen reported.
The finding, published in the journal Molecular Psychiatry, provides a possible explanation for how autism develops during pregnancy, countering fears that external factors such as vaccines play a role. Autism spectrum disorders, a group of brain development disorders, affect at least one child in 160, according to the World Health Organisation.
“We previously knew that elevated prenatal testosterone is associated with slower social and language development, better attention to detail and more autistic traits,” Simon Baron-Cohen, professor of developmental psychopathology at Cambridge, said.
The study drew on 19 500 amniotic-fluid samples stored in a Danish biobank from individuals born between 1993 and 1999. The researchers identified samples from mothers of 128 boys later diagnosed with an autism-spectrum condition.
“We now want to test if the same finding is found in females with autism,” Baron-Cohen said, pointing to the greater chances of autism affecting boys.
The study results suggest there’s variation in individual sensitivity to hormones or that the investigated time window is too early to detect a true elevation of hormone levels, said Richard Sharpe, a professor specialising in male reproductive health at the University of Edinburgh.
“Researching this in humans is incredibly difficult because of the obvious limitations in accessing what is happening in the foetus inside the womb, so investigations such as the present study have to be viewed as pioneering.”
A paper published in March in the New England Journal of Medicine found that those diagnosed with autism missed key genetic markers for brain cells that are supposed to develop prior to birth.
A Norwegian study published last year found that taking folic acid supplements in early pregnancy was linked to a lower risk of autistic disorder. Folic acid is needed to fuse the spinal cord in early foetal development.
Vaccination has been feared as a potential cause of autism after a study by Andrew Wakefield, published in the Lancet medical journal in 1998, linked the measles-mumps-rubella vaccine to an increased risk of developing the condition. The Lancet retracted the study in 2010, citing “false” claims, and the British Medical Journal called it a fraud in a report the following year.
A study published about 14 months ago in the Journal of Pediatrics by researchers at the Centres for Disease Control and Prevention in Atlanta confirmed earlier research findings that autism risk isn’t increased by the use of childhood vaccines. – Washington Post