Autism and mother’s anti-depressant use in pregnancy

Just over a year ago we addressed how research that had been presented in the media had linked Autism Spectrum Disorder (ASD) with the maternal use of anti-depressants during pregnancy. For a full read of that post see below. The issue has been raised again in the media following the publication of a meta-analysis (a big review of studies) on the topic. So how has the media handled reporting of this topic on this occasion?

How did the media handle reporting in 2017?

Reporting on this meta-analysis was very mixed. The most surprising aspect of all was the mixed response WITHIN the same media outlets. The Daily Mail reported that the study was showing that pregnant woman shouldn’t take anti-depressants, even stating that women who took anti-depressants during pregnancy were 81% more likely to have children with autism. The very next day however they reported on a paper that had been published from the same journal (Journal of the American Medical Association) that suggested that anti-depressant use in pregnancy was NOT associated with autism (or the developmental disorder ADHD). Quite confusing for the reader!

Other outlets were careful to point out that the meta-analysis had revealed that the higher association of autism in mother’s who had taken anti-depressants also was found in mothers who had taken the medication prior to pregnancy. This shows that the association likely comes about because it is to do with a relationship between mental health and developmental disorders rather than being associated with actual anti-depressant use within the pregnancy. This is of course the conclusion we came to in our posting on this topic back in 2015!  In general the findings of the two studies on this topic this week are reassuring of there not being a clear link between anti-depressant use within pregnancy and a risk of autism.

Our previous post on this topic (in 2015):

Autism spectrum disorder (ASD), and the factors that may cause it, are frequently discussed in the news. There have been reports in the media over the last week suggesting that maternal use of antidepressants during pregnancy ‘doubles the risk of autism’. The coverage generated highlights the need to follow our top tip of ‘Don’t stop at the headline’. What does ‘doubling’ the risk actually mean here, and are there alternative explanations that could account for any increased risk?

The study has been comprehensively described by the NHS Choices team and we would recommend anyone wanting to find out more about the specifics to read their thorough description and analysis of the study. We will focus on the media coverage which, fortunately, was mostly accurate. The exception to this was use of sensationalist headlines that, out of context, could raise fear and alarm in pregnant mothers taking anti-depressants. Both the Telegraph and Daily Mail ran with headlines that suggested that taking anti-depressants during pregnancy ‘doubles the risk’ of having a child with autism. When we get into the nuts and bolts of what this means it becomes clear that these headlines are unnecessarily sensationalist.

There are two key contextual issues to bear in mind here. Firstly, the ‘doubling’ that is referred to – terminology which will cause alarm – is numerically a very small risk. The diagnosis of autism in the overall sample was less than 1% (0.72% to be exact) – ‘doubling’ the risk raised the diagnosis rate to 1.2%, reflecting not even one extra child per 100. While the Daily Mail did refer to ‘doubling the risk’ in their headline, fortunately they were very clear in emphasizing the context of this in their sub-headlines. They pointed out that the absolute risk ‘remains tiny’ and provided the figure of 1.2% of children who developed autism whose mothers had taken anti-depressants. Clearly a very small proportion of children whose mothers take anti-depressants during pregnancy develop autism – almost 99% of those who take this medication do not go on to have a child with autism. It is good to see this emphasized in headings within reporting, albeit only as sub-headings.

While the researchers did control for maternal depression there may be other factors – whether genetic or environmental – that predispose a mother to depression and her child to autism. So the factors causing this small increased risk may not be anything to do with the actual anti-depressant treatment itself – something we call confounding variables in scientific research. The Huffington Post summed this up nicely – “the key problem is that women who take a medication when they are pregnant have a reason for taking it. Blaming the outcome on the medication, without considering the underlying disease, is like saying that umbrellas cause flooding. Taking away the umbrellas – “not treating the rain” – does not prevent flooding, it just means that people get soaked“. We gave similar examples in our posts on assessing risk and associations and causal relationships. Within the context of this anti-depressant study, more research is needed to identify the factors responsible for the small increased risk observed.

Boukhris, T. et al. (2015). Antidepressant Use During Pregnancy and the Risk of Autism Spectrum Disorder in Children. JAMA Pediatrics. DOI: 10.1001/jamapediatrics.2015.3356