Prenatal paracetamol/Tylenol exposure and offspring developmental outcome

CC BY-NC by inhuman tsar

In modern times, pain is generally no longer considered to be something which has to be tolerated or endured. A startling array of medicines is at our disposal to put the breaks on most cases of pain. So much so that several very effective forms of pharmaceutical pain relief can be readily picked up at a local pharmacy or even supermarket without a doctor’s prescription and many times, with little or no checks required despite often being very powerful medicines.

But as with all medicines, the various pain relievers available are not always side-effect free. Paracetamol also known as acetaminophen as well as being a particularly good form of pain relief and effective at reducing fever, has some notable issues associated with overdose related to liver damage for example. This mechanism also explaining why paracetamol enjoys a dubious distinction when it comes to its use as a self-poisoning agent whether accidental or deliberate.

Up until now, comparatively little has been mentioned in the research literature about any effects from typical paracetamol use during pregnancy particularly on the unborn child outside of data correlating a possible relationship with offspring asthma. The paper by Brandlistuen and colleagues* suggests however that prenatal exposure to paracetamol for a period longer than 28 days during pregnancy might be associated with several adverse outcomes on offspring neurodevelopment.

Describing data derived from a large Norwegian study of pregnant women and their offspring (shortened as MoBa), Brandlistuen and colleagues describe how when looking at several thousand sibling pairs – one exposed to paracetamol in-utero, the other not – several developmental milestones and functions seemed to be adversely affected by paracetamol use. This included functions pertinent to communication, motor behaviours and higher activity levels described in the exposed sibling. The authors report that the amount of exposure as measured by the length of time they were exposed to paracetamol during foetal development might also be a factor, and were also able to rule out such an association with other forms of common pain relief such as ibuprofen.

The authors have cautioned that this was a study of association and does not necessarily point to a causal relationship between pregnancy paracetamol use and issues with later offspring development. That being said, the numbers included in their study and their adjustment for other factors during pregnancy which could also affect offspring development, mean that the study findings certainly indicate the need for further investigation into this potentially important area.


* Brandlistuen RE. et al. Prenatal paracetamol exposure and child neurodevelopment: a sibling-controlled cohort study. Int J Epidemiol. 2013 Oct 24.


Further commentary on this study can be found here.