2.2 Prenatal experience
Prenatal brain development is the foundation for the long-term health and well-being of each child. Prenatal development is a complex process that takes place in the womb – or in utero – environment. In the context of prenatal brain development, both the biological contributions of the parents and the womb environment play important roles in how the fetal brain develops. Indeed, the health of the mother and father even prior to conception is important since the developing organism has its origins in the union of the sperm with the egg. A completely unique set of genes, inherited from these two combining sex cells, interacts with the prenatal environment to influence how development unfolds.
Recent research is providing insight into the influence of preconception health and lifestyle of both the mother and the father (and even the transgenerational influence of grandparents) on the developing fetus with implications for the child’s lifelong health and wellness. Listen as Sir Peter Gluckman, the inaugural chief science advisor to the Prime Minister of New Zealand, describes some of the preconception factors that can affect the growth and development of the fetus.
In 2018, The Lancet published a series of articles examining the importance of preconception health of the mother and father.
Development of the brain in the prenatal period
The prenatal period is a time of great sensitivity for the brain. Throughout the months of pregnancy, the brain, spinal cord, and nervous system gradually form. The next two readings describe how the fetal brain develops. The first is an overview of prenatal brain growth from the Zero to Three website and the second is a more detailed look at how the brain changes during pregnancy, in the newborn period and beyond.
Take the challenge below and identify the sequence of various processes involved in prenatal brain development.
More in depth information about how the brain develops is explained on The Brain from Top to Bottom website, starting with “How the Nervous System Begins” immediately followed by “How the Major Subdivisions of the Brain are Formed.”
Developmental Origins of Health and Disease
The fetal origins hypothesis as proposed by Dr. David Barker (1995) draws our attention to the extreme sensitivity of the fetus to negative environmental factors. As an epidemiologist, he noted associations between altered fetal growth from fetal undernutrition in the last half of gestation with coronary heart disease in adulthood. Subsequently, researchers have learned more about the detrimental impact of factors such as poor nutrition and prenatal stress. This hypothesis has more recently come to be understood as the developmental origins of health and disease (DOHaD). Listen now as Gluckman defines DOHaD.
In the next reading, learn more about DOHaD and examples of research in this emerging field of study.
Teratogens
“A teratogen is any agent that causes an abnormality following fetal exposure during pregnancy” (Genetics Alliance, 2014, Appendix D, para 1). Some of the known harmful influences that may occur during the three stages of prenatal development – pre-embryonic, embryonic, and fetal – which are described in the following reading.
In the next three video clips, listen to researchers discuss the impact of smoking, alcohol, and even noise on the fetus.
In the next video, listen as Dr. Maggie Morris, professor, Department of Obstetrics, Gynecology and Reproductive Sciences at the University of Manitoba, describes the harmful effect of smoking on the oxygen and nutrient supply that reaches the fetus.
In the next video, Dr. Joanne Weinberg, professor emerita and distinguished scholar in the Faculty of Medicine at the University of British Columbia, describes her research with animal models in establishing alcohol as a teratogen during pregnancy, and the advantages of using animal models in research.
Dr. Brian Kolb, University of Lethbridge, describes the results of a research study on noise as a stressor during pregnancy with subsequent impacts on the offspring.
Research continues to add to the body of knowledge regarding teratogens. The list of known industrial chemicals known to be toxic is increasing and as Grandjean and Landrigan (2014) state, “…industrial chemicals widely disseminated in the environment are important contributors to what we have called the global, silent pandemic of neurodevelopmental toxicity” (p. 330). Considering the unique vulnerability of the brain pre- and postnatal, there are increasing calls for action for testing, evaluation, and regulation in order to prevent exposure to neurotoxins.
The following two articles review research on the impact of toxins on early brain development.
The following meta-analysis provides global prevalence estimates of FASD among children and youth.
Maternal nutrition and prenatal brain development
The 2013 Lancet Series on Maternal and Child Nutrition point out “…nutritional conditions in adolescence, at the time of conception, and during pregnancy, as important for maternal health and survival, fetal growth and subsequent early childhood survival, growth, and development” (R. E. Black et al, 2013, p. 445).
Undernutrition or malnutrition can result in short and long term consequences for the developing fetus. Across the globe, certain difficulties may result in undernourishment of the fetus including social factors such as a short interval between pregnancies, a lack of antenatal care, intimate partner violence, low socioeconomic status, or challenges with food security.
In the next video, Dr. Steve Lye, professor in the Departments of Obstetrics & Gynaecology, Physiology and Medicine at the University of Toronto as well as executive director of the Alliance for Human Development, Lunenfeld-Tanenbaum Research Institute, describes three things the brain needs to develop well, beginning with maternal nutrition during pregnancy. Specifically, Lye identifies lipids, which are substances such as fatty acids, triglycerides, oils, and waxes. In the context of cell development, lipids are important in storing energy, and they help to form the outer layer of cells and are also involved in the formation of some hormones. Additionally, Lye talks about stimulation and protection from abuse, neglect, and violence – factors that come more into play following birth.
The following article by Mousa, Naqash and Lim (2019) looks at the research on the macro- and micronutrient needs during pregnancy and the consequences of deficiencies.
Maternal stress and prenatal brain development
As Lye identified, besides nutritional status, the maternal environment influences prenatal brain development through other factors such as the social and structural environment of the family and maternal lifestyle. The idea that adversity within families, particularly maternal prenatal stress, can influence fetal development and long-term health and well-being has been another important focus of recent research.
Listen to Dr. Alan Bocking, professor in the Department of Obstetrics and Gynaecology at the University of Toronto, describe examples of adverse physical environments that impact the fetus, including levels of maternal stress.
Bocking explains that maternal stress leads to an increase in the level of stress hormones in the body. Cortisol is a stress hormone that gets released into the bloodstream to help the body cope with more acute stressors. The hypothesis that maternal prenatal stress can influence fetal development and longer-term health and developmental outcomes is an area of active study in both animal and human research. Listen as Dr. Chris Kuzawa, professor and faculty fellow, Institute for Policy Research in the Department of Anthropology at Northwestern University, talks about the work of one of his former Ph.D. students and what her research findings revealed about the association of reported prenatal stress, maternal cortisol levels, and infant stress responses after birth.
The normal course of fetal brain maturation and development may be altered not only in situations where there is an acute maternal stress response (e.g., in situations where there is a death of a loved one), but also when a neuropsychiatric disorder, such as depression, exists in the mother (Ross & Desai, 2012, p. 91). Dr. Janet Werker, Canada research chair, Department of Psychology at the University of British Columbia, conducts research on early language development. In the next two videos, she describes a study that looked at whether infant language perception was affected when their mothers were depressed while pregnant. The study compared the babies of mothers who were not depressed with the babies of depressed mothers who took anti-depressant medication and mothers who did not take medication.
On the other hand, research is also demonstrating how nurturing care and stimulation can protect children from the effects of stress. Stronger maternal-fetal relationships have been associated with more sensitive and nurturing interactions between mothers and children after they are born (Foley and Hughes, 2018), which enhances the environment for both prenatal and postnatal brain development.
Supportive social and physical environments for families act as buffers to minimize maternal and family stressors and enhance well-being during pregnancy and beyond.
How would you describe a nurturing maternal-fetal relationship? How can this be promoted and supported?
In your context, what current “buffers” can you identify that help to minimize maternal and family stressors?
Considering a multi-sector approach who would you “invite to the table” in order to better support pregnant women and their families in your context?
