Fighting the stress of pregnancy
Anxiety during pregnancy is common, but new research shows that stress can harm a baby’s development, leading to long-term problems.
Being pregnant is stressful. In a perfect world we would see the little blue line of new life and then book nine months of yoga and pedicures. Most of us, however, keep working, move into a bigger, more run-down home and row with our partners about money. Yet new research shows that looking after ourselves during pregnancy could be the most important thing for our children.
In a survey of pregnant, largely middle-class, women at a London hospital, nearly a quarter felt anxious and depressed, while the same number argued often with their partners. These women’s babies had a lower birth weight, lower IQ, slower cognitive development and more anxiety than those born to the other women in the survey.
Although postnatal depression is a well-known condition, prenatal depression is more common and at least as damaging to the child, according to research by a professor of perinatal psychobiology, Vivette Glover, of Imperial College London.
It is known that being stressed during pregnancy is as bad for your baby as smoking or being obese (these findings were published in the Journal of the American Academy of Child and Adolescent Psychiatry in 2007) but now we know why and how.
Glover’s most recent research has shown that maternal anxiety affects the placenta, reducing the activity of the barrier enzyme that hinders the hormone cortisol from reaching the foetus. This means that women’s stress levels reach the growing baby on a physical level. This, in turn, has an impact on foetal brain development, a phenomenon that has been clearly demonstrated in animals.
“People used to think that if something was congenital, apparent at birth, it had to be genetic. In fact it can be an in-vitro reaction of genes and environment,” Glover says. Her research shows that pre-natal stress hugely increases the likelihood of a child having attention-deficit hyperactivity disorder, cognitive delay, anxiety and depression. Stress during pregnancy also increases the risk of the child being autistic and, in rare cases, schizophrenic. Stressed mothers also produce babies with lower birth weight, which can be an indicator for coronary heart disease in later life.
The largest British study of the effects of maternal antenatal stress was in Bristol, where thousands of women answered a questionnaire during pregnancy and then at regular periods for 15 years afterwards, describing their children’s behaviour. Postnatal depression was factored out and saliva tests monitored the children’s stress responses. Of the 15 per cent of women who had experienced the most stress and depression during pregnancy, the likelihood of their children having ADHD, conduct disorders, anxiety, depression and emotional problems was doubled.
“The data on anxiety and depression was taken during pregnancy at 18 weeks and again at 32 weeks, and the stronger result came from the later test. The organs are forming during the first trimester of pregnancy, but the brain is developing all the way through,” Glover explains. “The organs are sensitive while they are forming and, once formed, they are harder to change. Once ADHD is established, for example, it is very difficult to alter.”
To stem the tide of guilt washing over most mothers reading this, Glover says that she has new, unpublished, research to show that empathetic mothering can buffer against some of the adverse effects of stress and be “very positive”. Alas, for those of us who were stressed out of our minds during pregnancy and then went straight back to work, this is scant comfort.
Research by Sir Michael Rutter, a leading child psychologist, has produced evidence that mental health is worse in children today than in the past. This may be because women are more stressed during pregnancy, more likely to be single and less likely to be supported by their families.
“In evolutionary terms, stress perhaps prepares the child for survival in a stressful environment. If a child is anxious and has attention deficiency, it will be very alert to danger. This may once have been adaptive, beneficial for the child, but it isn’t any more,” Glover says. The research also suggests that the damage to the foetus caused by maternal stress can be passed on to the next generation.
The animal evidence on the damage caused by maternal stress is conclusive, Glover says. Research on rhesus monkeys, started by Harry Harlow in the United States, helped to revolutionise childcare in the 1950s, at a time when it was thought that too much physical contact with babies was a bad idea. Harlow’s unmothered monkeys were severely disturbed.
Mary Schneider, Professor of Occupational Therapy and Psychology at the University of Wisconsin-Madison, has taken up Harlow’s baton, showing that if you make a pregnant monkey stressed, her young will be more anxious and have a fear of being touched, which is common in autistic children. The structure of the young monkeys’ brains was also permanently altered, including a reduced volume of the hippocampus — an area important in stress responses and memory — and decreased right-left asymmetry in the brain — in other words, less difference between the function of the two halves of the brain. This may explain why children whose mothers have been stressed in pregnancy are more likely to be mixed-handed than right-handed.
Research into antidepressants using rats showed that when young were dropped into water, the progeny of unstressed mothers tried to get out, but those of stressed mothers allowed themselves to sink. When the previously anxious young were given the happy pills they also tried to swim.
So what can we do? Well, intervention helps. The Family Nurse Partnership, pioneered by David Olds in the US, is being adopted in the UK. Olds was working with deprived toddlers and realised that by the time the children were 3 a great deal of damage had already been done. He began to work with pregnant mothers, mainly young, single and poor, providing a weekly meeting with a nurse to help the women to gain some control over their lives.
The partnership lifts the women out of isolation and a lack of support, both big risk factors for depression and anxiety. This was a 30-year study and the crime rate among the children born to the scheme’s mothers halved, their health improved and their education was more successful.
“Health, education and crime should not be separated,” Glover argues. “Helping women starts with the health service, but the effects are social, especially as regards crime. ADHD, cognitive delay, conduct disorder — all the results of a stressful pregnancy — are indicative for crime. One study showed prenatal depression in the mother led to violence in the adolescence of the child. These issues are linked.”
We all want our children to be happy and well, and we would do pretty much anything to ensure it. It is interesting to know, then, that the best thing that we can do for our babies is to be happy ourselves — especially when we’re pregnant.
How to unwind
Eat foods containing B vitamins, such as wholegrains, which increase your levels of the anti-stress hormone serotonin.
Exercise is proven to ease tension. Swimming is perfect, as your bump is supported by the water.
Midwives say commuting is a big source of stress. Ask your employer if you can avoid rush hours by starting and finishing work earlier.
Look at books and websites such as www.mumsnet.com to help you to feel in control.
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