Exposure to paracetamol in the womb may increase the risk of autism among boys and undermine attention in both sexes.
At five years of age, 1,173 children underwent a battery of tests including the Childhood Autism Spectrum Test (CAST) and Conner’s Kiddie Continuous Performance Test (K-CPT), which evaluates attention, reaction time, accuracy and impulse control, and correlates with attention deficit hyperactivity disorder.
K-CPT omission errors occur when a child does not respond to a target stimulus. Commission errors occur when the child responds to a non-target stimulus.
Children exposed to paracetamol up to gestational week 32 were 41 per cent more likely to show hyperactivity or impulsivity symptoms than controls. K-CPT commission errors were commoner, while detectability scores were lower in those exposed to paracetamol. CAST scores were also higher in boys exposed to paracetamol.
“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,” remarks lead author Claudia Avella-Garcia, researcher at CREAL in Barcelona.
Many associations increased with frequency of paracetamol use. For example, children of women who persistently used paracetamol during pregnancy were about twice as likely to show hyperactivity and impulsivity symptoms as those whose mothers did not.
Several mechanisms may account for paracetamol’s effect. The drug, for example, stimulates the endocannabinoid system, which might affect neuronal differentiation, axonal migration and synapse positioning. Paracetamol may also affect testicular function and androgen production.
“The male brain may be more vulnerable to harmful influences during early life,” Dr Avella-Garcia says.
Int J Epidem Doi: 10.1093/ije/dyw115