A child is at greater risk of being born with autism (ASD) if the mother takes anti-depressants during pregnancy, new research suggests
The study, carried out by Canadian researchers, looked at medical history of 145,456 children whose mothers were part of the Québec Pregnancy/Children Cohort (1998-2009) and who were covered by the Régie de l’assurance maladie du Québec drug plan for at least 12 months before and during pregnancy.
In all 1,054 children were diagnosed with ASD (0.7%), on average at 4.5 years of age. Even allowing for other factors the study suggests an ASD diagnosis was significantly more likely if the mother had taken anti-depressants during the second and/or third trimester (14-40 weeks).
The risk was further enhanced if the anti-depressants used were selective serotonin reuptake inhibitors (SSRIs), such as Paxil, Zoloft and Prozac.
Professor Anick Bérard of the University of Montreal, who is a member of the research team, said:
‘We defined exposure to antidepressants as the mother having had one or more prescription for anti-depressants filled during the second or third trimester of the pregnancy. This period was chosen as the infant’s critical brain development occurs during this time.’
‘Amongst all the children in the study, we then identified which children had been diagnosed with a form of autism by looking at hospital records indicating diagnosed childhood autism, atypical autism, Asperger’s syndrome, or a pervasive developmental disorder. Finally, we looked for a statistical association between the two groups, and found a very significant one: an 87% increased risk.’
While the study couldn’t establish a definite causal link between autism and the use of SSRIs during pregnancy Professor Bérard said the findings warranted further research.
‘It is biologically plausible that anti-depressants are causing autism if used at the time of brain development in the womb, as serotonin is involved in numerous pre- and postnatal developmental processes, including cell division, the migration of neuros, cell differentiation and synaptogenesis – the creation of links between brain cells. Some classes of anti-depressants work by inhibiting serotonin (SSRIs and some other antidepressant classes), which will have a negative impact on the ability of the brain to fully develop and adapt in-utero.’