Monday November 19 2012
Stress during pregnancy may make children more sensitive
‘Stressful pregnancy could make children easier prey for bullies’, the Daily Mail reports, saying that anxiety during pregnancy can be passed on to the baby in the womb. It suggests that this could make children more sensitive to the effects of stress – such as crying or running away, when bullied.
This large study aimed to see whether a mother’s reported family adversity during pregnancy (such as financial problems) was associated with the child’s risk of bullying between the ages of 7 and 10.). The researchers also considered the effects of the mother’s mental health during pregnancy.
Notably, they found that family adversity during pregnancy increased the risk of the child being a victim of bullying, when looking at either child, parent or teacher reports of bullying, and at all assessment points between 7 and 10.
However, it is difficult to say for certain that it was family adversity, and the related stress to the mother during pregnancy, that was the direct cause for the increased risk of bullying. The researchers found that maternal mental health was also linked to risk of bullying, and that family adversity and maternal mental health were also linked to parenting style and parental arguments.
So it is difficult to pick apart the influence that other socioeconomic and environmental factors could be having upon the child, and conclude that any biological effects associated with maternal stress during pregnancy directly lead to increased feelings of stress in the child.
The researchers suggest that health services could target appropriate care towards families living in adverse circumstances, or where the parents have mental health problems. This could help prevent the child experiencing bullying or other health problems.
Where did the story come from?
The study was carried out by researchers from the University of Warwick and was funded by the Medical Research Council (UK), the Wellcome Trust and the University of Bristol.
The study was published in the peer-reviewed Journal of Child Psychology and Psychiatry.
The Daily Mail reporting is representative of this research, though it doesn’t address the complex interplay between parental health, socioeconomic circumstances, parenting style and other environmental influences that are likely to be involved.
It is also worth noting that the media has only associated the story with pregnancy stress.
However, the study used validated scales to examine the experience of what were presumed to be stressful life events (known as the Family Adversity Index), such as financial difficulties, drug and alcohol problems, and involvement with crime (as well as the state of maternal mental health during pregnancy).
Whether these adverse experiences would actually cause the mother stress is only assumed.
What kind of research was this?
This was a cohort study that specifically aimed to examine whether stress during pregnancy – due either to family adversity or mother’s mental health – increases the likelihood that the child will be a victim of bullying.
They also aimed to look at whether pregnancy stress has a direct link, or whether any link could be mediated by other confounding factors, such as parenting practices or conflict between the parents.
The researchers were investigating the theories of ‘foetal programming’ and ‘Developmental Origins of Health and Disease’. These theories are based on the principle that the conditions that the developing baby is exposed to in the womb could have an effect on the child.
Animal research has previously observed that when pregnant animals are subject to stress, it can have an effect on the behavioural and stress responses of the offspring.
There have also been some human studies showing that children of mothers who are stressed during pregnancy can be at increased risk of behavioural or emotional disorders and depression.
What did the research involve?
This study included participants of the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. This is an ongoing cohort study which was set up to investigate how individual circumstances affect issues such as development, health, and disease during childhood and into adult life.
The study initially recruited 14,541 women resident in Avon who were due to give birth between April 1991 and the end of December 1992.
From the first 12 weeks of pregnancy onwards, parents completed postal questionnaires about themselves and in addition, after the baby was born, about the child’s health and development.
Children were invited to attend annual clinic assessments, which included psychological and physical tests from seven years of age onwards.
The current study is based on 8,829 children who had at least four separate assessments of bullying (or ‘peer victimisation’) by child, parent, or teacher report.
Child reports of bullying were collected when the children were aged 8 and 10 years and used a validated scale called the Bullying and Friendship Interview Schedule. Questions assessed whether the child had experienced:
- ‘Overt victimisation’ assessed by five questions about whether the child: had personal belongings taken, had been threatened or blackmailed, had been hit or beaten up, had been tricked in a nasty way, had been called bad or nasty names.
- ‘Relational victimisation’ assessed by four questions about whether the child: had been excluded to upset him/her (for example, not allowed to ‘join in’ with games), been coerced to do things they did not want to, had lies or nasty things said about them, had their games spoilt.
Overt victimisation and relational victimisation were judged as being present if the child confirmed that at least one of the behaviours occurred repeatedly (four or more times in the past six months) or very frequently (at least once per week in the past six months).
A child was considered to be a victim of bullying if she or he was a victim of overt or relational victimisation.
Parent and teacher reports of bullying were assessed using the Strengths and Difficulties Questionnaire, a widely used questionnaire which assesses a young person’s mood, behaviour and situation..
Parents completed this questionnaire when the child was on average 6.7, 8 and 9.5 years old. Teachers completed the questionnaire when the child was 7 and 10.
The questionnaire included the answer option ‘child is picked on or bullied by other children’. If the response was ‘applies somewhat’ or ‘certainly applies’ on any of the assessments by parent or teacher, the child was considered victim of parent or teacher-reported bullying.
During pregnancy the Family Adversity Index had been used to assess multiple potentially stressful events affecting the family (family stressors) at 8, 12, 18 and 32 weeks of pregnancy. The Index consists of 16 items assessing issues such as financial difficulties, crime involvement, and use of alcohol or drugs. Responses were classed as none, mild and severe.
Maternal mental health was measured using the Crown-Crisp Experiential Index and the Edinburgh Postnatal Depression Scale at 18 and 32 weeks of pregnancy. Both of which are well-validated methods of assessing maternal mental health.
When assessing the relationships between pregnancy stress and being a victim of child bullying, the researchers took into account many confounders that had been assessed during the pre-school years, including:
- parental mental health
- family adversity during the pre-school years
- parenting style (such as shouting or hostility towards the child)
- partner conflict
- child temperament (assessed using the Toddler Temperament Scale at two years of age)
What were the basic results?
The researchers found that there was significant agreement between child, mother and teacher reports of bullying.
In the model fully adjusted for all measured pre-school confounders, severe family adversity during pregnancy was associated with significantly increased risk of bullying, by child, mother or teacher report, and at all assessments points (7, 8, 9 and 10 years).
Experiencing mild family adversity during pregnancy was associated with significantly increased risk of child reported bullying at 8 and 10 years, but not with mother or teacher reported bullying at any time point.
They found that maternal mental health problems during pregnancy were also independently associated with risk of bullying.
The researchers then adjusted their results for the following confounders:
- family adversity during pregnancy
- parenting style
- parent conflict
- child temperament
After these adjustments, they continued to find that if a mother experienced mental health problems during or before pregnancy then this was associated with increased risk of the child being a victim of bullying as assessed by the child (at age eight), mother (both time points), or teacher (at age seven).
Both maternal mental health and family adversity also increased the risk of maladaptive parenting style (such as shouting or hitting the child) and partner conflict, which independently increased the risk of victimisation.
How did the researchers interpret the results?
The researchers conclude that ‘experiences in pregnancy may affect the developing foetus and increase vulnerability to be victimised by peers’. They say that conflict between parents and also their parenting style may further increase the risk of being victimised at school.
This research found that the mother’s report of family adversity during pregnancy (such as financial problems, drug or alcohol use, or crime involvement) significantly increased the risk of the child being a victim of bullying. Notably, the risk increase was significant when looking at child, parent or teacher reports, and when looking at all time points this was assessed at between the ages of 7 and 10 years.
This research has many strengths, including its prospective study design, large sample size, multiple assessment points, and the use of validated scales to gain information on the experience of family adversity and maternal mental health during pregnancy, and looking at whether the child was a victim of bullying.
However, it is difficult to say for certain that it was pregnancy stress that was the direct cause for the increased risk of bullying and that confounding factors were not having an influence.
As the researchers demonstrated, the mother’s experience of mental health problems either before or during pregnancy were also independently associated with an increased risk of the child being a victim of bullying. Then both the mother’s mental health and family adversity during pregnancy were associated with increased likelihood of maladaptive parenting style, and with parent conflict.
So it is difficult to pick apart the influence that parental mental health problems, socioeconomic factors, family adversity, and environmental factors could be having upon the growing child and how these factors could then influence their risk of victimisation at school.
It is also worth noting that while the media has associated the story with pregnancy stress, the study used validated scales to examine the experience of family adversity during pregnancy. But the researchers never asked whether these events actually caused the woman to feel ‘stressed’.
Whether these adverse experiences would cause the mother stress is only assumed.
The researchers appropriately suggest educational and health services should be more aware of the fact that children living in families with a history of adverse events and /or mental health problems may require additional support.
Hopefully, focusing care on more vulnerable children may help prevent them from experiencing bullying or other health problems.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on twitter.