Stress during pregnancy bad for baby’s brain
Scientists in Singapore uncover link between parents' behaviour and how young brains develop
Put a group of children in a playground and all of them may seem happy. But, under the skin, some may already be well on their way to developing depression, addictions or other mental disorders.
Scientists in Singapore have uncovered how the stresses of pregnancy and poor parenting choices may affect children's brains and hurt them later in life.
They found that when women are more anxious during pregnancy, the children's brains tend to grow more slowly in the first six months of life compared to the offspring of relaxed mothers.
When children are abused, genes in their brains that respond to stress also become more active, causing them to suffer more, and more easily, from stress later in life.
Even emotional neglect can leave physical marks. These so-called epigenetic marks are chemical modifications of DNA that control the activity of genes.
In a Canadian study that looked at two types of rat mothers - those that licked their pups a lot and those that did not - the pups that were licked more produced less cortisol, a stress hormone, when they were provoked.
This could mean that, for infants, a parent's touch could be far more than just warm and comforting: It could set them up to be more stable people who are not easily panicked.
Being able to identify these physical changes that occur in the brain would allow doctors and authorities to more effectively single out which children and families need help, said Professor Michael Meaney from the Agency for Science, Technology and Research (A*Star).
The 60-year-old noted that the epigenetic changes are reversible. "It's not that an individual's fate is cast in stone in early life, and therefore unalterable. Quite the opposite," he said.
The Canadian citizen led the rat study as a professor of psychiatry and neurology at that country's McGill University. He is still a professor there, and is now also director of the Integrative Neuroscience Programme at A*Star's Singapore Institute for Clinical Sciences (SICS).
This week, he will be awarded the 2014 Klaus Jacobs Research Prize from the Swiss charity Jacobs Foundation, for his work in how parental behaviour affects children's brain development and lifelong function.
He intends to use the 1 million Swiss francs (S$1.35 million) prize money to fund local and overseas research that uses biology studies to find out how to identify and help the vulnerable children.
He said that, currently, authorities tend to use blunt indicators such as poverty to predict risk. "But many children grow up in poverty without family dysfunction and major health problems," he said.
"What we need to do is to understand the impact of social adversity on the individual child."
He noted that such personalised treatment is already available for some physical diseases: "In heart disease, we can take a blood sample, look at it, and say to the person, you need lipid-reducing medicine, or you are likely to benefit from physical exercise."
Singapore's Gusto (Growing Up in Singapore Towards Healthy Outcomes) study, which Dr Meaney and SICS are involved in, is one such attempt to identify the epigenetic imprints of parents' choices and mental well-being.
It began in 2009 with some 1,200 expectant women, and the researchers are still tracking their children, who are now three to 41/2 years old.
Originally intended to shed light on how metabolic diseases arise from early life, it has branched into other areas such as allergies and the developmental advantages of babies exposed to multiple languages.
Dr Meaney is also working with institutions in the United States, the Netherlands and Canada to study the effectiveness of intervention methods.
The programmes each involve hundreds of at-risk mothers. These include women who were themselves abused early in life, do not have stable marital relationships, live in poverty or suffer from drug addiction.
Some of the women, while they are pregnant and for two years after their children are born, get regular visits from nurses, who advise on maternal health, parental care and more. All of the children will also be observed until they are in their early adulthood.
DNA will be collected from the children and divided into groups, depending on whether the child's parents received help and whether the child is doing well. The researchers hope to identify epigenetic marks that predict treatment outcomes for individuals.
"Ideally, we would be able to say that children who carry this or that biochemical marker are more likely to benefit from intervention," Dr Meaney said.
He said anxiety and attention deficit disorders, and even some forms of depression, can occur in children before they are 10 years of age. "By the time the children approach puberty, you can also start to see evidence of addictions, depression, and more, so we don't have that long to wait."
Most mental disorders occur in late childhood and early adolescence, he added.
But the findings have to be verified in a different cohort of children, so reliable results could take many more years.
While the foreign studies may involve Caucasians, the findings will be applicable to Asians. "Unlike for, say, heart disease and diabetes, there appears to be a universal set of conditions that render the brain vulnerable and mental health disorders more likely to occur," he said.
Asked for his advice for new parents, Dr Meaney suggested setting aside time for each other and the family.
"I know that's simplistic, especially when you have families where both parents may have to work, and work long hours, to make a living. But it really is the parents' emotional well-being, and their interactions with their children, that will determine the long-term health outcomes."
Societies, including the authorities, also need to examine the demands placed on parents. He added: "We cannot underestimate the importance of social relationships and families.
"That's something we need to cling to."