Taking paracetamol during pregnancy is linked to autism and ADHD in children, a new study claims. Boys whose mothers took the painkiller while expecting were more likely to be on the autistic spectrum while it was associated with higher rates of ADHD in both sexes.
Official guidelines say paracetamol should be taken only if necessary in pregnancy and for the shortest possible time. The latest study by Spanish researchers suggests children regularly exposed to the common medication while in the womb were more likely to show signs of both conditions.
In what has been hailed the first study of its kind, it looks at the association between the use of this drug in pregnancy and autism spectrum symptoms in children. Scientists say it is also the first study to report different effects on boys and girls.
They found those whose mothers took the drug regularly were 30 per cent more likely to show impaired attention functions and an increase of two clinical symptoms of autism spectrum symptoms in boys.
The study recruited 2,644 mother-child pairs in a birth cohort study during pregnancy.
Of these, 88 per cent were evaluated when the child was one year old, and 79.9 per cent were evaluated when they were five years old.
Mothers were asked about their use of paracetamol during pregnancy and the frequency of use was classified as never, sporadic, or persistent.
Exact doses taken could not be noted as the mothers were unable to recall them precisely.
It found 43 per cent of children evaluated at age one and 41 per cent assessed at age five were exposed to any paracetamol at some point during the first 32 weeks of pregnancy.
When they were again assessed at age five, exposed children were at higher risk of hyperactivity or impulsivity symptoms.
Persistently exposed children in particular showed poorer performance on a computerised test measuring inattention, impulsivity and visual speed processing, the study found.
Boys also showed more autism spectrum symptoms when persistently exposed to paracetamol.
Lead author Claudia Avella-Garcia, researcher at CREAL, part of the Barcelona Institute for Global Health, explained they tested for symptoms rather than exact diagnoses.
'Although we measured symptoms and not diagnoses, an increase in the number of symptoms that a child has, can affect him or her, even if they are not severe enough to warrant a clinical diagnosis of a neurodevelopmental disorder.'
Co-author Dr Jordi Júlvez, said there were several reasons why paracetamol could be harmful to neurodevelopment.
'First of all, it relieves pain by acting on cannabinoid receptors in the brain.
'Since these receptors normally help determine how neurons mature and connect with one another, paracetamol could alter these important processes,' he said.
'It can also affect the development of the immune system, or be directly toxic to some fetuses that may not have the same capacity as an adult to metabolize this drug, or by creating oxidative stress.'
There could also be an explanation for why boys are more likely to have autism spectrum symptoms, Professor Garcia said.
'The male brain may be more vulnerable to harmful influences during early life', she said.
The study concluded that the widespread exposure of infants to paracetamol in the womb could increase the number of children with ADHD or autism spectrum symptoms.
However, they stressed further studies should be conducted with more precise dosage measurements, and that the risks versus benefits of paracetamol use during pregnancy and early life should be assessed before treatment recommendations are made.
The findings were published this week in the International Journal of Epidemiology.
Commenting on the study, Professor Alan Cameron, of the Royal College of Obstetricians and Gynaecologists, said: 'Paracetamol is one of the most common medicines used to reduce a high temperature and ease pain, it is safe and is used routinely during all stages of pregnancy.
The preliminary results from this study suggest that frequent paracetamol use throughout pregnancy may impact attention function and slightly increase the risk of hyperactivity in the offspring at aged 5 years old.
'No effect on cognitive, motor or social development was identified.'
He added: 'It is important to highlight from these results we cannot determine a direct link between paracetamol usage and any neurodevelopmental problems.
'Future studies should take into account dosage as well as other possible contributory factors. However, women should not be alarmed by the results of this study and we recommend that pregnant women continue to follow current guidance and take the lowest effective dose for the shortest possible time when necessary.
'If the recommended dose of paracetamol doesn't control symptoms or pain, seek advice from your midwife, GP or obstetrician.'
Daily Mail Cullage