The drug increases the risk by around 30 per cent: the autism risk is almost exclusively in boys and ADHD can affect both genders, researchers from the Centre for Research in Environmental Epidemiology in Barcelona say.
They questioned 2,644 mothers a year after they had given birth, and again five years later. Around 43 per cent said they had regularly taken paracetamol during the pregnancy, although few could recall the exact doses they had been taking.
The children whose mothers had regularly, or ‘persistently’, taken the painkiller were more likely to suffer from hyperactivity or some impulsive behaviour.
The researchers surmise that the drug could be affecting neuro-development in the fetus by interfering with receptors in the brain that determine how neurons mature and connect with each other. It also affects the development of the immune system.