Effects of antenatal stress on fetal and child neurodevelopment Flashcards
LO:
- Embryo-fetal environment: Summarise how the extrauterine environment can impact embryo and fetal development and health across the life-course.
- Child and adoslescent development: Summarise the key developmental milestones of child and adolescent development and expected timeframes.
- Women have as many symptoms of depression and anxiety during pregnancy as postnatally
- Pregnancy can also be a time of increased domestic abuse and relationship strain
Fetal programming-environment starts in the womb
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.
The fact that it is called programming doesn’t mean that it is set in stone eg sensitive early mothering after can help.
Sensitive early mothering…
The Fetal Brain is “Under Construction”
Depends on signals it receives by the mother inutero.
Synapses start to form
P MDS P
second p for pruning until puberty!
Long term effects of prenatal stress on neurodevelopment:
Types of prenatal stress reported to be associated with increased risk of changes in cognitive development and behavior in the child.
Daily hassles eg arguments etc. are on lesser end but can also affect the child’s development.
Pregnancy speciifc anxiety-worry about the pregnancy will she and her child be okay.
Prenatal stress associated with
Increased risk for child :
ØAnxiety and Depression of child
ØBehavioural problems-ADHD, conduct disorder
ØImpaired cognitive development, they do less well in exams
ØNeonatal behaviour
ØMore difficult infant temperament
ØVictimisation in childhood-more likely to be bullied probs due to mixture of these things
ØSchizophrenia ( associated with extreme stress and stress in first trimester as this is when cells are migrating and in schizophrenia there is an altered pattern of migration of cells.)
Ø Autism spectrum
ØPersonality disorder
Prenatal stress associated with
increased risk for (physical outcomes):
Decreased telomere length-bits at end of chromosome that protect it. This is associated with how long a person lives and so suggestive if stressful pregnancy, child will actually have a shorter lifespan.
Are associations causal? Some people say mother is depressed and so have gene for this and child is just inheriting this gene.
Is it causal, rather than genetic or postnatal?
What studies have been done:
- Animal studies-lots, compare stressed animals to unstressed animals
- Effects of natural disasters-not genetic as all children in area where event occured are affected
- Studies which allow for confounders
- Underlying mechanisms
ALSPAC-large cohort which starts at pregnancy rather than birth
Avon longitudinal study of parents and children
Have complete data of over 7000 women and children
Have paternal data
Have all the confounders we wanted data on.
If Mother is in top 15% at age 13, child had double the risk of probable mental health disorder.
-This is only an increase in risk, so most children aren’t affected.
- For top 15% of most anxious/depressed women in pregnancy, rate of probable mental disorder
- Doubled from about 6 to 12% at age 13 years (after multivariate analysis allowing for a wide range of possible confounders).
- Attributable load of probable mental disorder in whole population due to prenatal anxiety/depression ~10%
Genetic, prenatal and postnatal environment are 3 main factors
The effects of antenatal depression are very similar to postnatal-but with post it is psychlogical, but antenatal is biological.
The Strengths and Difficulties Questionnaire (SDQ) is a brief emotional and behavioural screening questionnaire for children and young people.
- Why are some children affected and not others?
- Why are they affected in different ways?
- Gene-environment interactions?
Looked at COMT (Catechol-O-methyltransferase) which inactivates catecholamines, we all have different forms of this gene.
Given 3 numbers and asked to repeat in reverse orders
If child had blue or green gene of COMT they were resistant and had no effect from maternal environment, but if had red gene then there was a gene environment interactions and if at 32 weeks maternal anxiety was present, this had a much greater effect. Without gene there is only a slight increase.
Underlying mechanisms-what is going on, how does mother’s stress in pregnancy affect child?
Animal studies on HPA axis.
If stress a pregnant woman, cortisol doesnt go up as much as in animal, so dont really know what is going on in mother.
But placenta is important as it filters what goes through to the foetus, it is very rich is enzyme that breaks down cortisol to prevent it getting to foetus.
Placenta rich in:
enzyme that breaks down cortisol
( 11-β hydroxysteroid dehydrogenase type 2 (HSD2) oxidizes the biologically active glucocorticoid (GC), cortisol, to inactive cortisone.)
More anxious the mother was, the lower the expression of the enzyme.
(Cortisol, serotonin and immune system are all likely to be affected. Note-antenatally, the baby is affected biologically but postnatally, the baby is affect psychologically. Stress alters the sex as male is more prone to stress in uterine so females more likely to give birth to males)
If mother is anxious or depresed it allows for down regulation of enxyme in placenta so foetus is exposed to more enzyme in the placenta.
If child is insecurely attached, there was a negative correlation
If securely attach, it seemed to completely buffered.
fMRI study-bought children back for fMRI
Other MRI studies of effects of prenatal stress on child brain
Increasing evidence that prenatal stress is associated with lots of cognitive problems, it seems that the increased exposure to cortisol increases this change in brain.
Epigenetic modifications-basis for fetal programming
Article showing gradmothers who are associated to domestic violence, the grandchild has epigenetic changes.
WHY? Why should prenatal stress has all these effects on the child?
Predictive adaptive value of changes due to prenatal stress
in a stressful environment (predators)in the wild?
Ancestors were likely to be stressed if there were real stressors outside eg snakes, so fear and anxiety is associated with increased vigilence so always looking around somore likely to see predators
ADHD-distracted by any noise so more likely to detect predators
Evolutionary benefit of changes caused by prenatal stress
Conduct disorder-lash out and so more likely to attack predator
Autistic-understand things in different ways to helpful for group to think about stuff in different ways.
What should be done?
Role of Professionals-
Much more than with diagnosed mental disorders
Other professionals like midwives should be aware that it isn’t just medical problems to deal with but to reduce stress and help the couples and paternal relationship and stress.
Other ways to reduce antenatal stress:
Study in Gambia, with singing and dancing antenatal classes
Control group who hadn’t been in antenatal singing and dancing class
Can breastfeeding help
cognitive and emotional/behavioural outcomes?
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
