More support needed for pregnant women, as researchers report relationship between maternal stress and the development of white matter in the baby’s brain
Our recent study published in Biological Psychiatry reported an association between maternal prenatal stress and white matter development in premature neonates.
Why was this important to study
Stress, anxiety and depression affect a large number of women during pregnancy. However, there is much we still don’t understand about the relationship between maternal stress during pregnancy and the development of the baby. A few studies have suggested that babies of mothers who experience anxiety or depression during pregnancy may cry more or may be more difficult to soothe. There is also some evidence to suggest that these babies may then go on to be at increased risk for developing neurodevelopmental or psychiatric disorders later in life. However, these studies are difficult to interpret, as there are many postnatal influences that may better account for these effects (such as parenting, socioeconomic status etc). Because of this, we decided to examine the baby’s brain development as early as possible – a few weeks after birth. In this way, any effects that we see are less likely to be due to postnatal influences. Later on, we plan to follow up these children when they go to school, in order to see whether their brain development around the time of birth is related to their emotional and psychosocial development.
What we did
In this study, we asked 251 women to complete a stressful life events questionnaire, in which they were asked to indicate which events they experienced in the previous year. The events ranged in severity from quite severe (such as divorce or bereavement) to less severe (such as taking an exam or moving house). All of these women had babies who were born prematurely (between 23 and 33 weeks) and we invited them to bring their babies for an MRI scan at term equivalent age (between 37 and 45 weeks).
We analysed the images of the baby’s brains with a technique called “Diffusion tensor imaging”. This technique allowed us to look at the development of the white matter tracts (which are fibres that connect different brain areas to each other). An easy way to understand what white matter tracts are is to think of the map of a city – the buildings are the grey matter and the roads are the white matter. We looked at a specific white matter tract called the uncinate fasciculus – this roughly connects the frontal areas of the brain, to the limbic system and then temporal lobe. The reason why we looked at the uncinate fasciculus tract specifically was that in previous studies, changes in the microstructure of this tract have been found in adults with anxiety disorders and those who experienced early life stress.
What we found
We found that maternal stress was associated with changes in the white matter microstructure of the uncinate fasciculus of the babies (i.e. higher stress associated with increased diffusivity). This relationship was not found in any of the control tracts (i.e. the tracts in which we did not expect to find an effect).
What this means
This study is a step forward in our attempts to understand the relationship between maternal stress and the baby’s brain development. We found it interesting to see that these changes can be observed so early on (at term equivalent age). For now, we do not know whether the changes we observed in white matter have any relationship with the baby’s development. Our next step will be to invite these children back for further studies when they are older. We can then look at the relationship between their brain scans when they were babies, and their development later on. Until then, we cannot draw any conclusions about what these results mean.
It is also important to note that baby’s brains are very plastic. Several studies done by other research groups have suggested that early interventions (such as having the expectant mothers attend therapy sessions during pregnancy or in the postnatal period) can mitigate the effects of maternal stress on the baby’s development.
We hope that the results of this study will help inform early interventions and influence policy making, with the hope that outcomes for both mothers and their children will be improved.
Perinatal Mental Health Resources:
Press Coverage (list not exclusive)
The Scotsman, Irish Examiner, Greenock Telegraph, This study was covered extensively by the media - sometimes relatively well, but sometimes not so much so. This blogpost (rather than any quotes from newspaper articles) represent the views of the first author on the overall message that our study is trying to communicate. Our focus is on improving outcomes for both mothers and their babies.