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Childhood Behavior Linked To Taking Acetaminophen In Pregnancy

An association between paracetamol intake and hyperactivity and attention problems has been identified in a new study. The research investigated if there were any effects of taking paracetamol in mid-pregnancy and the behaviour of the offspring between the ages of 6 month and 11 years, with memory and IQ tested up until the age of 17.

Paracetamol, also known as acetaminophen, is commonly used to relieve pain during pregnancy.

Using questionnaire and school information from Bristol’s Children of the 90s study, researchers looked at data on 14,000 children. When they were seven months pregnant 43 per cent of their mothers said they had taken paracetamol ‘sometimes’ or more often during the previous three months. Researchers examined results of the children’s memory, IQ and pre-school development tests, temperament and behaviour measures.

Hyperactivity And Attentional Problems

The researchers found an association between paracetamol intake and hyperactivity and attention problems as well as with other difficult behaviours with young children that were not accounted for by the reasons why the medication was taken or social factors. However, this was no longer the case by the time the children reached the end of primary school.

Boys appeared to be more susceptible than girls to the possible behavioural effects of the drug.

The longitudinal cohort study was led by Professor Jean Golding OBE who also founded the University of Bristol’s Children of the 90s study.

“Our findings add to a series of results concerning evidence of the possible adverse effects of taking paracetamol during pregnancy such as issues with asthma or behaviour in the offspring. It reinforces the advice that women should be cautious when taking medication during pregnancy and to seek medical advice where necessary. It is important that our findings are tested in other studies—we were not in a position to show a causal link, rather an association between two outcomes. It would also be useful now to assess whether older children and adults are free of difficult behavioural problems if their mother had taken paracetamol,”

Golding commented.

Thalidomide Echoes

The thalidomide tragedy of the late 50’s and early 60’s involved a seemingly benign drug being taken for a condition that is common in early pregnancy – nausea and vomiting. Its birth-defect inducing effect was discovered because many of the offspring were born with striking and unusual malformations.[2]

Since then, there has been a concern that relatively common adverse effects would not be easily identified, especially if they were not apparent immediately after the child was born. Few such effects have been discovered, but few drugs taken in pregnancy have been investigated for outcomes that would take many years to be recognised. This is particularly (but not exclusively) true of over‐the‐counter medications, currently the most common of which is paracetamol.

In general, despite evidence that paracetamol crosses the placenta[3] and is a known endocrine disruptor[4] and a COX inhibitor, the medical profession is relatively tolerant about the use of this analgesic in pregnancy; it is usually claimed to be the analgesic of choice. It is true that it has not been implicated in major malformations, but there has been consistent evidence that women who take paracetamol in pregnancy increase the risk of their child developing asthma[5].

This current study examined paracetamol between 18 and 32 weeks, but not in early or late pregnancy. A follow-up should be done to assess whether the childhood effects seen here are accompanied by difficulties in scholastic achievements, or whether any adverse effects survive puberty, the authors note.

[1] Golding, J, Gregory, S, Clark, R, Ellis, G, Iles‐Caven, Y, Northstone, K. Associations between paracetamol (acetaminophen) intake between 18 and 32 weeks gestation and neurocognitive outcomes in the child: A longitudinal cohort study. Paediatr Perinat Epidemiol. 2019; 00: 1– 10. https://doi.org/10.1111/ppe.12582

[2] Neil Vargesson. Thalidomide‐induced teratogenesis: History and mechanisms. Birth Defects Res C Embryo Today. 2015 Jun; 105(2): 140–156.

[3] Levy G, Garrettson LK, Soda DM. Evidence of placental transfer of acetaminophen. Pediatrics. 1975;55:895‐895.

[4] Bernard Jégou. Paracetamol-induced endocrine disruption in human fetal testes. Nature Reviews Endocrinology volume 11, pages 453–454 (2015).

[5] Henderson AJ, Shaheen SO. Acetaminophen and asthma. Paediatric Respirat Rev. 2013;14:9‐16.