The impact of paracetamol on children’s health has also been aired. A Norwegian study published in February 2016 involving over 53,000 children found “independent modest associations between asthma at three years with prenatal paracetamol exposure and use of paracetamol during infancy.”¹³ The increased risk of asthma in children whose mothers had taken paracetamol during pregnancy was 13 per cent. Secondary analysis indicated that prenatal ibuprofen exposure was positively associated with asthma at three years, but not asthma at seven years.

Responding to this, the PAGB pointed out that the study was observational, rather than an RCT, with results “based on questionnaires completed at various intervals over a long period of time. The limitations of this type of study are well known and the authors acknowledge that their work does not account for the amount of paracetamol taken or the severity of the condition it was taken to treat, therefore it is impossible to understand whether the paracetamol was taken within guideline levels.” A study author advised that the findings should not affect current guidance regarding paracetamol use in pregnancy.¹⁴

Researchers have also been investigating the possibility that paracetamol taken during pregnancy can have behavioural effects on the child. Results from one UK longitudinal observational study with a cohort of 7,796 mothers found increased odds of the child having conduct or hyperactivity problems, or an increased likelihood of emotional symptoms, if paracetamol had been taken during the pregnancy.¹⁵

A Spanish study with a cohort of 2,644 mother-child pairs had also concluded that prenatal paracetamol exposure “was associated with a greater number of autism spectrum symptoms in males and showed adverse effects on attention-related outcomes for both genders.” Associations seemed to depend on exposure frequency.¹⁶

In response, the PAGB pointed out again that this was an observational study, and that “these preliminary results should not concern pregnant women, [as] these conditions are extremely complex and authors conclude that further studies are needed.”¹⁷

A US National Institutes of Health preliminary study following 501 couples suggested that pregnancy may take longer where paracetamol is being used, particularly by males, based on testing urinary paracetamol concentrations. However, the researchers also pointed out that “participants were not asked to provide information on indication of use for paracetamol medications; any underlying conditions for the paracetamol use would have been potential confounders.”¹⁸

It should also be noted that paracetamol is “one of the compounds produced when the body breaks down aniline, a chemical used to make rubber, pesticides, and coloring agents used in food, cosmetics and clothing,” so extrinsic factors may also be at play.^19