Stress and Fetal Development PDF

Thursday, February 1, 2024 Stress and Fetal Development Stress starts impacting a person from conception - the effect of stress on the foetus can have lifelong implications Barker’s hypothesis: Coronary heart disease, Type 2 diabetes, stroke and hypertension originate in developmental period/plastic...

Thursday, February 1, 2024 Stress and Fetal Development Stress starts impacting a person from conception - the effect of stress on the foetus can have lifelong implications Barker’s hypothesis: Coronary heart disease, Type 2 diabetes, stroke and hypertension originate in developmental period/plasticity, in response to undernutrition during fetal life - Stress during sensitive periods in fetal development may explain the origin of adult diseases Programming hypothesis (expansion of Barker’s) - Non-genetic factors can organize or imprint permanently on physiological systems - Maternal stress can directly affect the structure and function of biological systems Whatever impacts the developing foetus will impact its development and features The baby enters life with everything that’s already happened - can be good or bad Opportunities and SES also will have an impact but the most important is what happened in the womb HPA AXIS - estrogen increases cortisol production increases during pregnancy = cortisol increases during pregnancy - ↑ cortisol is bound - ACTH secretion ↑ - Cortisol production ↑ - cortisol increases until free cortisol back to original level - free cortisol inhibits the ACTH secretion - cortisol inhibits immune system to prevent it from overreacting and attacking healthy cells and tissue 1 Thursday, February 1, 2024 - why pregnant women have increased cortisol blood levels, but not the symptoms of - glucocorticoid excess bioavailable levels of cortisol remain the same until 25 weeks gestation same for women taking estrogen containing oral contraceptives Stress affects the sympathetic nervous system Stress affects HPA taxis > cortisol > affects placenta Cortisol directly affects the foetus Stress releases adrenaline Adrenaline & cortisol affects developing foetus Positive Aspects GLUCOCORTICOID IN FETAL DEVELOPMENT - Cortisol is part of the normal development Influence growth in uterus, activity of pancreas, HPA axis & cardiovascular activity Maturation of organ system Triggers birth: end of pregnancy ↑ in level of glucocorticoid - Trigger of mechanism that leads to birth But if cortisol is too high it may be aversive - Postnatal survival & postnatal adaptation Cortisol helps with survival - Especially premature babies Certain levels of stress may be beneficial - Accelerate lung maturation, decreases respiratory distress syndrome in premature infants MODERATE LEVELS OF STRESS MAY BE BENEFICIAL FOR OPTIMAL DEVELOPMENT - Sensitizes developing nervous system - Develop adaptive response to stress - Rats: bene ts later learning The closer to the optimal level of cortisol in the foetus, the higher the learning Cortisol is necessary for development Too high levels or too chronic = aversive Physiological impact of maternal stress - ↑ infant mortality and preterm births Especially common in women under high levels of stress - ↓ birth weight and head circumference - Decreased foetal movement & heart rate - HPA axis response (too high or too low) fi 2 Thursday, February 1, 2024 - Brain structure Too much stress on mom will impact the developing foetus PRETERM BIRTHS AND LOW BIRTH WEIGHTS - Inuterine Growth Restrictions (IUGR) = birth weight