Stress and Pregnancy: How It Affects the Brain of the Unborn Child
Introduction
All parents want to have healthy and happy children and when pregnant they will make every effort to eat well, take the proper supplements, and avoid recreational drugs, alcohol and cigarettes. What few of them are unaware of unaware of is the destructive power on their unborn children of parental stress.
While most people understand what is meant by the word stress actually, the concept is quite difficult to define. For our purposes, suffice it to say that stress denotes both the internal and external demands that we face to accommodate change. Stress becomes negative when adaptation or coping mechanisms fail. However, stress is very subjective. What may be horrifying to even contemplate for me may be savored by another, like bungee jumping for example.
Stress Hormones
One group of stress hormones is called catecholamines and they consist of adrenaline and nor-adrenaline. These are manufactured in the inner core (the medulla) of the adrenal gland, a small gland that sits on top of the kidneys. So, when a person feels stressed, the so-called Fight or Flight Response is initiated and adrenaline and nor adrenaline are injected by the adrenal gland into the circulation. This system is part of the autonomic nervous system (the other part is the para-sympathetic system) and referred to as the sympathetic nervous system. It increases heart rate, blood pressure and blood sugar production. Also, because the body is being readied for fight or flight, blood is diverted from the internal organs such as the stomach and the intestines to the large muscles of the legs (so you can run better) and the arms (obvious).
Stress During Pregnancy
The uterus as an internal organ, suffers the same fate as the gastro-intestinal tract, having its normal blood supply diminished. What that means for a pregnant woman is that at times of stress her baby will receive less blood and, therefore, less oxygen and nutrients. If this state persists, the consequences can be dire. It should be added that stimulation of the sympathetic system is accompanied by inhibition of the parasympathetic system. The latter promotes rest, sleep and digestion. Its inhibition leads to wakefulness and malabsorption of food. As you can see the Fight or Flight Response is well suited for a person being chased by a lion but not so great for a pregnant mother’s unborn child. There is another aspect to the body’s reaction to perceived threat. And that occurs by way of what is called the HPA Axis.
This system works beautifully under normal conditions. It is “designed,” for lack of a better term, to preserve homeostasis (equilibrium) or, at times of stress, to restore homeostasis as quickly as possible. It is a feed-back loop apparatus similar to the heating systems of most apartments or houses where a thermostat is set at a certain temperature. When the temperature in the room falls, below the set temperature, the thermostat will signal to the furnace and the furnace will heat up. After a while the house heats up sufficiently for the thermostat to tell the furnace to shut down. Everything stops until the room cools and then the whole process starts again. Similarly, with the body. If a pregnant woman runs to catch a streetcar, she will experience stress but after she reaches the streetcar and sits down, her system will quickly return to normal. No harm was done.
On the other hand, if this pregnant woman experiences an acute stress such as the death of a loved one or loss of a job, or is a single mother worried about how she will support the child she is carrying, her amygdala in response to these ruminations will override signals from the hippocampus (“Hey! Stop that! There is enough cortisone in the blood already!”), and stoke the fires in the adrenals so they keep making more cortisone, adrenaline and nor-adrenaline. In either case, her body is flooded with stress hormones.
Thus, we have two possibilities. A short-lived major flooding of the mother’s and consequently her baby’s body with stress hormones or, a higher-than normal concentration of stress hormones over a protracted period of time. In either case, high levels of stress hormones are detrimental to the health of the mother and her unborn child.
Stress and the Developing Brain
Research has shown that abnormally high and prolonged concentrations of cortisone have many harmful effects on the developing baby. In this paper we shall explore how they affect the construction of their brain.
The brain develops from the outward-most layer, the ectoderm, of the very early embryo. The neural cells travel from the neural tube to form the six layers of the cerebral cortex. Each layer has its distinct pattern of organization and connections.
Each cell is genetically programmed to journey to a particular location in the brain. This means that under normal conditions, a neuron which for illustration purposes we shall call A ends up at point X and there connects with neuron B. Great. But what if there are large concentrations of cortisone, nicotine or other neurotoxic substance in the brain?
High concentrations of cortisol in the brain will lead to cell migrations to the wrong destinations resulting in the formation of abnormal neural circuits. If this state is prolonged (chronic stress), a large concentration of stress hormones will create a massive destruction of neurons, their synapses and their dendrites (each neuron receives messages from other neurons by way of up to 15,000 fine hair like branches called dendrites). When this process occurs in the hypothalamic and reticular activating systems it will interfere with the child’s internal states such as sleep and digestion. When widespread cell destruction happens in the amygdala and hippocampus it will interfere with information entering the brain freely.
Excessive and sustained stress also leads to a marked decrease of neurons in the prefrontal cortex resulting in an increased dominance of lower brain centers over higher centers.
Stress also decreases the production of oxytocin, the so-called love hormone and increases the production of vasopressin, a hormone that supports aggressive behaviour.
The sustained secretion and circulation of glucocorticoids such as cortisol
eventually leads to a depletion of dopamine, which decreases activity in the pleasure pathways of the brain; reduction of norepinephrine, resulting in a lack of motivation and alertness; and a lowering of serotonin, reducing feelings of happiness and well-being.
Due to a confluence of all these factors, this child will have a very strong propensity to develop a Personality Disorder.
Summary
Unfortunately, stress during pregnancy may handicap a child from before they are even born. For this reason, assuring a stress-free pregnancy for all women should be a priority of all government public health programs.
Key Takeaways
Psychological stress during pregnancy produces lasting undesirable changes in both, mothers and their children.
A severely stressed mother’s unborn child will very likely be born with a miswired brain.
Consequently, as the child grows older, they will suffer of a decreased capacity to learn and remember which may predispose to poor academic performance and a downward spiraling to truancy and delinquency.
It is imperative for the health of this planet that primary prevention starts in the womb not years later.
References
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DeMause, Lloyd (1982). Foundations of Psychohistory. Creative Roots Pub. New York, NY.
Marsh, Abigail A.; Blair R. J.R et al. (2008). Reduced Amygdala Response to Fearful Expressions in Children and Adolescents with Callous-Unemotional Traits and Disruptive Behavior Disorders. Am J Psychiatry, 165:712-720.
Maya Opendak, Elizabeth Gould. Adult neurogenesis: a substrate for experience-dependent change. Trends in Cognitive Sciences, 2015; DOI: 10.1016/j.tics.2015.01.001
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