Effects of Antenatal Stress on Fetal and Child Neurodevelopment Flashcards
How can the mother affect the development of the foetus?
Mother’s emotional state in pregnancy and in the early postnatal period
can have a long lasting effect on her child
How do ante-natal depression and post-natal depression vary?
Just as many women experience ante-natal anxiety / depression as post-natally
Where does a child’s environment begin?
In the womb - mother’s emotional well-being affects child’s development
What is fetal programming?
Environment in womb = long-lasting affect on fetus
Environment in the womb, during different sensitive periods for specific outcomes, can alter the development of the fetus, with a long lasting effect on the child
What can counteract some of the negative fetal programming?
Sensitive motherhood = Sensitive early mothering helps attachment, and can counteract some of what happens in the womb
How does the fetal brain form in the womb?
Signals it receives from the mother
Neurons proliferate from 5 weeks gestation through 18 months after birth
Then neural pruning continues til puberty
What are the long term effects of prenatal stress on neurodevelopment?
Increase risk of changes in cognitive development and behaviour in the child
What are the different maternal antenatal stresses associated with increased risk of changes in cognitive development and behaviour in the child?
Maternal anxiety and depression
Maternal daily hassles
Pregnancy specific anxiety - is my baby alright? am I alright?
Domestic abuse = upped during COVID; partner or family discord
Distress caused by war
Experience of acute disasters e.g. freezing ice storm, hurricane or 9/11
It’s not just extreme or toxic stress, or diagnosed mental illness
What are the possible associated cognitive risks / outcomes of antenatal stress?
Anxiety and Depression Behavioural problems-ADHD, conduct disorder Impaired cognitive development Neonatal behaviour More difficult infant temperament Victimisation in childhood Schizophrenia ( stress in first trimester) Autism spectrum Personality disorder
More likely to be bullied - unknown cause but deemed to be due to increased risk of the other things
What medical conditions are associated with increased risk in the child due to antenatal stresses?
Increased risk for: Reduced birthweight and gestational age Preterm delivery Mixed handedness Decreased telomere length Asthma Altered immune function Altered microbiome (in meconium)
Are associations causal, rather than genetic of postnatal?
Yes - many pieces of supporting evidence from: Animal studies Effects of natural disasters Studies which allow for confounders Underlying mechanisms
What is the ALSPAC?
Avon Longitudinal Study of Parents and Children -
Large prospective birth cohort ~14,000 pregnant women recruited around Bristol in 1990-1991
What did ALSPAC collect data on?
Lots of data collected on: Maternal Postnatal anxiety and depression Paternal pre and postnatal anxiety Parenting Maternal age Birthweight Gestational age Smoking Alcohol Psychosocial factors: crowding (SES) Maternal education
n= 7,363 with complete data
What did the ALSPAC reveal?
If the mother is in the top 15% of those with anxiety, the child had double the risk of a probable mental disorder
The combined effects of raised anxiety doubled from 6% to 12% at age 13 (similar results with depression)
Attributable load of probable mental disorder in whole population due to prenatal anxiety/depression~10%
Why are some children affected and not others, and why in varying amounts?
Gene-environment interactions e.g. COMT gene is different in most people, switching it on and off is therefore different in most people
What is the significance of the COMT gene?
COMT inactivates catecholamines – dopamine, adrenaline and noradrenaline
Gene variants are associated with working memory and ADHD
There are 2 working memory genes, A and G - giving rise to the genotypes GG, AA and AG
How dot hey affect working memory at aged 8 and child ADHD at age 15?
AG and AA = normal working memory and risk of ADHD development despite maternal anxiety at 32 weeks gestation
GG gene = declining working memory and increased risk of ADHD with maternal anxiety at 32 weeks gestation
Birthweight, gestational age, maternal education, maternalage, household crowding, maternal smoking, alcohol consumption, postnatal mood and parenting controlled for
What are the undrlying mechanisms to how mother’s stress during pregnancy affects the child?
Maternal stress / anxiety / mental illness = increase in cortisol, pro-inflammatory cytokines etc. in maternal blood = too much for placenta to filter out completely = cortisol passes through to foetus and affects growing foetus
What is the role of the placenta?
Interface between mother and fetus
Filters what comes in from the mothers blood and enters the fetus
How is the foetus exposed to more cortisol?
Increase in maternal cortisol in response to stress
Normally 1/11Beta-HSDS2 enzyme found in placenta = an enzyme that breaks down cortisol into cortisone before it enters the foetus, so cortisol itself cannot enter the foetus
In more anxious mothers, lower expression of this enzyme
Mothers is stressed - down-regulation of enzyme
Allows more cortisol to pass from mother to foetus
What is the significance of the increased amniotic cortisol and so increased exposure of cortisol to the foetus?
Strong negative correlation between amniotic cortisol and IQ in children who are insecurely attached to their mothers
Those who were securely attached - this acted as a buffer. No correlation
What are the Bayley Scalesof Infant Development (BSID-II)?
A scale used to study child’s cognitive development - especially to look for developmental delays and aid in intervention planning
What patterns are observed with increased utero exposure to cortisol?
Associated with lower cognitive function, reduced attention and increased anxiety = can be reversed with sensitive early mothering
Similar to those observed in children with early maltreatment
What did the Sarkar et Al study show?
fMRI study with 32 children contacted at ages 6-9 asked to do tasks that assessed sustained attention and the effects of reward
Results correlated with amniotic fluid cortisol and antenatal life events
What do MRI studies show of antenatal stress on the child’s brain?
Structural MRIs show: Thinner cortex (associated with depression and cognitive problems) Enlarged amygdala (associated with increased anxiety)
Diffusion MRIs show:
Alterations in uncinate fasciculus which connects the amygdala with frontal cortex (associated with mood disorders and antisocial behaviour)
What are epigenetic modifications as a basis for foetal programming?
Functionally relevant modifications
to the genome that do not involve a change in nucleotide sequence.
Can persist to grandchild generation
What is the adaptive value of changes to child’s brain due to prenatal stress?
Evolution -
Predictive adaptive value of changes due to prenatal stress in a stressful environment e.g. predators in the wild?
Anxiety/fear reactivity-beneficial effects of more vigilance
ADHD - shifting attention helps if predators about
What are the evolutionary benefits of other changes caused by prenatal stress?
Impulsive - more willing to explore new environments
Conduct disorder - more willing to break rules
Aggressive - fight predators or other tribes
Cognitive deficit - side effect of ADHD or autism spectrum
Autism spectrum - understand things in different ways
What is the role of professionals?
Detect and treat anxiety and depression both in pregnancy and postnatally
Help with relationship problems or domestic abuse
Help to create more social support
Practical help with housing etc
Help to teach sensitive mothering
What can help reduce antenatal stress?
Yoga
Gardening
Music
What can help after the baby is born?
Sensitive mothering e.g.
Stroking babies - can help reverse some of the effects of antenatal anxiety e.g. reduce number of emotional and behavioural problems as the child grows up
Breastfeeding can help with IQ and hyperactivity - but not emotional problems and conduct disorder
Does breastfeeding reverse the effects of antenatal stress on the child’s neurodevelopment?
No
Breastfeeding did not moderate the associations between prenatal depression and anxiety and child neurodevelopment, suggesting separate mechanisms of action.
Is it the effects of nursing or contents of breast milk that aids IQ?
Babies bottle fed breast milk did better on cognitive and memory tests than those fed formula milk
Shows it is the contents of breast milk help that cognition
What are the public health implications of reducing stress/anxiety/depression in pregnancy?
More than one million children in UK suffer from neurodevelopmental disorders
Attributable load of neurodevelopmental problems due to prenatal stress 10-15%
Potential to reduce number of affected children in the UK by 100,000-150,000
