June 20, 2024

expert reaction to study looking at prenatal maternal psychological distress during the pandemic and newborn brain development

A study published in JAMA Network Open looks at maternal psychological distress and newborn brain development during the pandemic.

Prof Grainne McAlonan, Clinical Professor of Translational Neuroscience, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London, said:

“In my view this paper uses unjustifiably alarming language in parts and is not especially a paper about Covid.  Rather it is a paper about possible response of the early brain to maternal stress during pregnancy and stress unsurprisingly was higher during Covid.  There are some statistically significant differences reported but these are on average group differences and most of the data from the groups compared actually overlaps.  Whether this difference is clinically meaningful was not established (there are no childhood outcomes) so assigning a value to brain volume differences by using words like “stunted” is entirely inappropriate and not supported by the data – especially when the groups overlap so much.  In general, in brain imaging studies, bigger brain regions are not necessarily better unless there is a clear relationship between brain size and a brain function.  The authors do not look at this.  Difference does not equal deficit necessarily and some differences may be compensatory.  We already know the brain is responsive to its environment and that includes the fetal brain.  All that has been shown here is a possible brain response to maternal stress during pregnancy and a very small effect at that.  We cannot tell whether it’s good or bad.

“There are many finer details that could be noted.  The stress measures were captured during pregnancy and so much earlier than the brain scan.  The sample of 56 collected during Covid is small and many more participants were collected pre-Covid.  The period of data collection during Covid was 2020-2022 – a long time and 2020 experiences of Covid were likely to be very different from 2022 experiences.  We also know that many pregnant women (like the general population) had Covid infections without symptoms and therefore often undetected, so we cannot say for certain any findings are solely related to maternal stress.  The measure used to group women into a high and low distress category was any passing of a threshold score on any one of different instruments.  Distress is complex, variable and exists on a continuum and using this kind of cut-off may not be optimal.  The authors explain their findings of white matter difference in relation to myelination, but for many tracts this does not happen by birth anyway.  Another thing they did not do was assess whether smaller regions were proportional to the volume of the whole brain.  They discuss that some fetal findings in a previous study do not persist – why did they not look longitudinally across timepoints if they had the data.  Similarly I suspect these neonatal findings may not persist but we certainly will need more work on the area.”

‘Prenatal Maternal Psychological Distress During the COVID-19 Pandemic and Newborn Brain Development’ by Susan Weiner et al. was published in JAMA Network Open at 16:00 UK time on Thursday 20 June 2024.

DOI: 10.1001/jamanetworkopen.2024.17924

Declared interests

Prof Grainne McAlonan: “I have a potential conflict of interest in that I lead the clinical studies within our Brain Health in Gen2020 programme which will examine outcomes of children who were in the womb during Covid. https://www.kcl.ac.uk/research/brain-health-in-gen2020”