UNIT 2 - Pregnancy and Stress |
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Maternal Psychosocial Stress and Epigenetics Maternal Stress and Fetal Development Maternal Practices and Child's Eating Behavior Maternal Diet and Child Health Article review Video review |
OBJECTIVES:
- Discuss the role of psychosocial stress in epigenetics
- Identify the effects of maternal stress to fetal development.
- Understand effects of maternal practices in child's eating behavior
- Discuss the influence of maternal diet to child health
Maternal Psychosocial Stress & Epigenetics
The prenatal period constitutes a crucial ontogenic developmental window where environmental influences have a preponderant effect on shaping fetal physiology by means of epigenetic mechanisms. One of the most complex organs to rapidly develop is the brain, which presents its fastest rate of expression change during the fetal period. Furthermore, the intrauterine environment is thought to be essential not only for fetal development itself but also for long-term health and disease, as prenatal environment risk factors, such as fetal nutrition, have been associated with a number of adult conditions, such as cardiovascular disease, which has encouraged the notion of a certain programming. Although early plasticity allows a proper adaptation to the environment that enables survival until reproductive age, it might be deleterious for both mental and physical long-term health.
Maternal stressors experienced during pregnancy that may influence offspring health include: i) physical stressors, such as malnutrition and toxins like alcohol, nicotine, or polychlorinated biphenyls; ii) psychosocial chronic stressors, such as suffering from a psychiatric disorder, taking care of terminally ill relatives, or being exposed to continuous violence (e.g., domestic violence or living in a war zone) or poverty (e.g., famine or low socioeconomic status); and iii) being exposed to severe incontrollable acute trauma (e.g., natural disaster, terrorism, or genocide), which may result in post-traumatic stress disorder (PTSD) development. It is important to note that these prenatal stressors do not present isolated but rather tend to converge. Intriguingly, the experience of chronic stress together with the development of anxious-depressive spectrum disorders have been associated with the onset of glucocorticoid resistance and higher circulating levels of cortisol, whereas PTSD has been consistently described to involve a higher glucocorticoid sensitivity and decreased cortisol levels. Due to this dual nature of cortisol effects after exposure to psychosocial stressors, we will focus on chronic conditions that have been described to increase circulating cortisol levels of pregnant women.
The human fetal hypothalamic-pituitary-adrenal (HPA) axis is developed and functioning at week 22 of pregnancy, although its plasticity is maintained during the first 2 years of life. Thus, maternal experiences of stress during pregnancy have the potential to permanently alter the physiology of their offspring, especially to program the HPA axis functioning. As the HPA axis regulates a myriad of biological processes, such as metabolism, blood pressure, and the immune response, these alterations can predispose prenatally stressed individuals to suffer metabolic, cardiovascular, and mental disorders in adulthood.
Maternal stressors experienced during pregnancy that may influence offspring health include: i) physical stressors, such as malnutrition and toxins like alcohol, nicotine, or polychlorinated biphenyls; ii) psychosocial chronic stressors, such as suffering from a psychiatric disorder, taking care of terminally ill relatives, or being exposed to continuous violence (e.g., domestic violence or living in a war zone) or poverty (e.g., famine or low socioeconomic status); and iii) being exposed to severe incontrollable acute trauma (e.g., natural disaster, terrorism, or genocide), which may result in post-traumatic stress disorder (PTSD) development. It is important to note that these prenatal stressors do not present isolated but rather tend to converge. Intriguingly, the experience of chronic stress together with the development of anxious-depressive spectrum disorders have been associated with the onset of glucocorticoid resistance and higher circulating levels of cortisol, whereas PTSD has been consistently described to involve a higher glucocorticoid sensitivity and decreased cortisol levels. Due to this dual nature of cortisol effects after exposure to psychosocial stressors, we will focus on chronic conditions that have been described to increase circulating cortisol levels of pregnant women.
The human fetal hypothalamic-pituitary-adrenal (HPA) axis is developed and functioning at week 22 of pregnancy, although its plasticity is maintained during the first 2 years of life. Thus, maternal experiences of stress during pregnancy have the potential to permanently alter the physiology of their offspring, especially to program the HPA axis functioning. As the HPA axis regulates a myriad of biological processes, such as metabolism, blood pressure, and the immune response, these alterations can predispose prenatally stressed individuals to suffer metabolic, cardiovascular, and mental disorders in adulthood.
Maternal Stress and Fetal Development
Human and animal studies have demonstrated that perturbations in early life, especially in the critical developmental window of intrauterine life, have programming effects on health outcomes in later life. A growing body of literature has also demonstrated that prenatal maternal stress (PNMS) can adversely impact a variety of developmental outcomes in the offspring throughout childhood that persist into adulthood. Epigenetics is considered to be one of the most important mechanisms involved in the long-term effects of in utero stress exposure. In the present review, we summarize the body of human research, exploring the association between fetal experience and epigenetic change, especially DNA methylation. Evidence reported here from research on genes that are associated with intrautrine adversity has shed light on how DNA methylation patterns may mediate biological processes involved in stress regulation. Furthermore, we provide evidence about these associations that have been reported from Project Ice Storm, a human model of the effects of PNMS on subsequent child and adolescent development.
Maternal exposure to a severe stressor, such as environmental pollutants, nutritional factors, psychosocial stress, or maternal depression during pregnancy, can increase the fetus’ risk for suboptimal growth in a wide range of somatic systems, and for developing a variety of disorders in adulthood. Effects of PNMS on fetal and child development, such as immune function, brain development, and behavior outcomes, have been largely discussed, although most of the research has been in laboratory animals. In humans, as depression and anxiety disorders are common mental health problems during pregnancy, their impact on epigenetic changes has also been widely investigated.
Maternal exposure to a severe stressor, such as environmental pollutants, nutritional factors, psychosocial stress, or maternal depression during pregnancy, can increase the fetus’ risk for suboptimal growth in a wide range of somatic systems, and for developing a variety of disorders in adulthood. Effects of PNMS on fetal and child development, such as immune function, brain development, and behavior outcomes, have been largely discussed, although most of the research has been in laboratory animals. In humans, as depression and anxiety disorders are common mental health problems during pregnancy, their impact on epigenetic changes has also been widely investigated.
Maternal Practices and Children's Eating Behavior
The first year of life is a period of rapid physical, social and emotional growth, during which eating patterns also develop. During this first year, infants transition from consuming a single food (i.e., breast milk or formula) to consuming a variety of foods more characteristic of an adult diet. This transition allows infants to learn about food through direct experience, as well as through observation of others' eating behaviours.
Data indicate that breastfeeding and parental modeling in the toddler years play significant roles in establishing longer-term eating behaviours. As reviewed below, children who are not breastfed still derive a significant benefit from the behaviours that their parents impart as they grow and develop. Breastfeeding is recommended as the optimal feeding method for the first 6 months of life, in part because of the mounting evidence that breastfeeding has a positive impact on the development of a child's later eating behaviours.
Breastfeeding plays a role in the development of a child's response to internal hunger and satiety cues, and may foster the development of self-regulatory abilities during feeding. Variations in the composition of breast milk during a single feed, as well as differences in composition across the first months of life, foster this heightened sensitivity to energy intake. Emerging scientific evidence also supports the role of breastfeeding in early metabolic imprinting, which partially accounts for later differences in eating behaviours. Breastfeeding also has a positive impact on later eating behaviour because it may promote acceptance of flavours in the maternal diet that are passed through breast milk. As a result, breastfed infants are exposed to a more varied flavour experience, depending on the variety of the mother's diet and this exposure may affect food acceptance during the transition to solid foods and later in life.
Infants are born with a preference for sweet and salty taste, thus sweet and salty foods have a greater likelihood of being accepted by infants when compared to foods with bitter flavours, such as certain vegetables. Both infants and young children can learn to accept a greater variety of foods and flavours through repeated exposure. Thus, in a sense, breastfeeding gives the infant early, repeated exposure to the flavours of the mother's diet, providing a flavour bridge that promotes the infant's acceptance of familiar flavours when they appear in solid foods. As a result, breastfed infants may be more accepting of new foods and likely to consume a more varied diet later in life, depending on the variety of the mother's diet during breastfeeding.
Data indicate that breastfeeding and parental modeling in the toddler years play significant roles in establishing longer-term eating behaviours. As reviewed below, children who are not breastfed still derive a significant benefit from the behaviours that their parents impart as they grow and develop. Breastfeeding is recommended as the optimal feeding method for the first 6 months of life, in part because of the mounting evidence that breastfeeding has a positive impact on the development of a child's later eating behaviours.
Breastfeeding plays a role in the development of a child's response to internal hunger and satiety cues, and may foster the development of self-regulatory abilities during feeding. Variations in the composition of breast milk during a single feed, as well as differences in composition across the first months of life, foster this heightened sensitivity to energy intake. Emerging scientific evidence also supports the role of breastfeeding in early metabolic imprinting, which partially accounts for later differences in eating behaviours. Breastfeeding also has a positive impact on later eating behaviour because it may promote acceptance of flavours in the maternal diet that are passed through breast milk. As a result, breastfed infants are exposed to a more varied flavour experience, depending on the variety of the mother's diet and this exposure may affect food acceptance during the transition to solid foods and later in life.
Infants are born with a preference for sweet and salty taste, thus sweet and salty foods have a greater likelihood of being accepted by infants when compared to foods with bitter flavours, such as certain vegetables. Both infants and young children can learn to accept a greater variety of foods and flavours through repeated exposure. Thus, in a sense, breastfeeding gives the infant early, repeated exposure to the flavours of the mother's diet, providing a flavour bridge that promotes the infant's acceptance of familiar flavours when they appear in solid foods. As a result, breastfed infants may be more accepting of new foods and likely to consume a more varied diet later in life, depending on the variety of the mother's diet during breastfeeding.
Maternal Diet and Child Health
Studies looked at protein intake and infertility and found that the type of protein influenced pregnancy rates. For those eating more animal protein, the relative rate of infertility was 1.39 compared to 0.78 for those eating more vegetable protein. Other studies looked at the use of multivitamin supplementation and found that micronutrients have a positive epigenetic effect resulting in 41% lower rates of infertility, fewer miscarriages, fewer birth defects, less pediatric cancer, and less autism. Another study looked at the role of micronutrients in the periconception period. Compared to women who did not take multivitamins, those taking less than 2 tablets per week had a relative rate (RR) of infertility of 0.88. Those taking 3 to 5 tablets per week had a RR of 0.69, and those taking more than 6 tablets per week had a RR of only 0.59. This means the rate of pregnancy was better for those taking more vitamins— more evidence that nutrition make a significant difference.
It was also reported that women who took iron supplements had a significantly lower risk of infertility. The adequate dose appeared to be 40 to 80 mg of iron daily. Studies in epigenetics also reveal that diet in the male partner also affects fertility. In the journal Human Reproduction, they looked at Danish males who ate mostly saturated fat and found 38% lower sperm concentration and 41% lower sperm counts. Similar studies in the United States found that walnuts improved but alcohol and cannabis impaired male fertility. Once we realize that external exposures affect genetic function, we start to question when preventive health care should start. The answer seems to be in the preconception period, but it is extremely concerning to know that the average in utero fetus has over 200 chemicals in the cord blood. This information makes the recommendation for preconception preventive health care even more important. Preconception recommendations should start 4 to 6 months prior to conception and should recommend stopping as many unhealthy foods as possible, avoiding as many environmental chemicals as possible, increasing the consumption of water and cruciferous vegetables, and considering detoxification. Health care providers should also discuss the impact of all the above with couples considering pregnancy. Pediatricians and gynecologists should talk with their patients about the use of vitamins, iron, and so on.
Nutrition and lifestyle before and during pregnancy, lactation, infancy and early childhood have been shown to induce long-term effects on later health of the child, including the risk of common non-communicable diseases such as obesity, diabetes and cardiovascular disease. This phenomenon is referred to as “Early metabolic programming of long-term health and disease” or “Developmental origins of adult health and disease”.
To strengthen the evidence base, researchers from 36 institutions across the European Union, the United States, and Australia collaborate in the European Commission funded “EarlyNutrition Research Project” (http://www.project-earlynutrition.eu). This international multidisciplinary research collaboration explores how nutrition and metabolism during sensitive time periods of early developmental plasticity can have an impact on cytogenesis, organogenesis, metabolic and endocrine responses as well as epigenetic modification of gene expression, thereby modulating later health. Because of the global escalation in the prevalence of obesity, particular focus has been placed on the developmental origins of adiposity (i.e., body fatness), leading to increasing evidence that early life programming could contribute to the intergenerational transmission of obesity and associated health outcomes.
To strengthen the evidence base, researchers from 36 institutions across the European Union, the United States, and Australia collaborate in the European Commission funded “EarlyNutrition Research Project” (http://www.project-earlynutrition.eu). This international multidisciplinary research collaboration explores how nutrition and metabolism during sensitive time periods of early developmental plasticity can have an impact on cytogenesis, organogenesis, metabolic and endocrine responses as well as epigenetic modification of gene expression, thereby modulating later health. Because of the global escalation in the prevalence of obesity, particular focus has been placed on the developmental origins of adiposity (i.e., body fatness), leading to increasing evidence that early life programming could contribute to the intergenerational transmission of obesity and associated health outcomes.
Article Review
Maternal mental health in pregnancy and child behavior
Maternal Stress and Fetal Neurobehavioral Development
Parental Influence on Eating Behavior
Maternal Stress and Fetal Neurobehavioral Development
Parental Influence on Eating Behavior
Video Review
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Unit Task
- Conduct an interview and assessment with at least two mothers of young children. Evaluate and document their lifestyle during prenatal stage using the forms you've been using from the previous tasks. Start providing information about the influence of maternal stress and lifestyle. Create a written summary of your activity and include the personal reflection (verbatim) of your clients.
- Submit your Reflective Journal after watching the videos, reading the lesson and article.