The Powerful Influence of the Prenatal Environment

            There’s no way around it, our society maintains an almost obsessive focus on pregnancy and childbirth. Pregnant women are bombarded with endless advice to take these supplements, do these types of exercise, and eat this, not that. The media flock around celebrities who announce that they’ll be having a child. Strangers approach women in the grocery store, asking to touch their stomachs. But what’s really happening in there? How significant is the prenatal environment for a child’s healthy development? And with this information, what can pregnant women and their partners do to improve the health of their children?

            The 38 weeks of a standard pregnancy is a time of immense, mind-boggling growth and development. Within weeks of conception, as the young embryo begins to develop a nervous system, several hundred thousand nerve cells are being created every minute (Sheridan & Nelson, 2009). As the embryo continues to develop, neuroblast cells travel to genetically-programmed areas in the brain and begin to create specialized neural networks (Sheridan & Nelson, 2009). Months pass, and the fetus slowly begins to interact with its prenatal environment. Touch becomes the first sense the baby uses to explore its surroundings (Cozolino, 2014).

            By birth, significant development has already occurred in the infant’s brain. The HPA axis, which is largely responsible for the human stress response, is fully online as soon as an infant enters the world (Sheridan & Nelson, 2009). Evolutionarily, this makes sense. A fully-wired stress response helps newborns appraise their new surroundings and facilitates their attachment to a caregiver who can meet their needs and help to regulate their HPA activation. However, the degree of sensitivity of the infant’s response is directly related to their prenatal experience.

            In their research, Davis and Sandman (2010) describe how a newborn’s stress response is directly related to the mother’s stress during pregnancy. Pregnancy is inherently stressful, and it’s expected for women to demonstrate higher levels of the stress hormone cortisol as they approach their due date. In fact, it’s healthy for the fetus to experience and learn to accommodate elevating levels of stress (Davis & Sandman, 2010). However, an excess of stress during pregnancy, especially during the earlier months, becomes problematic (Davis & Sandman, 2010). The researchers explain how prolonged, excessive cortisol exposure is linked to higher stress reactivity, poorer cognition, impaired brain development, and other neurodevelopmental delays after birth (Davis & Sandman, 2010). These types of high-sensitivity infants, in comparison to those who developed under healthier levels of stress, may pose more challenges for their caregivers and have a lower likelihood of developing a secure attachment relationship later in childhood.

            Vaughn (2014) also describes how cortisol and other prenatal toxins can impact a child’s executive functioning, or ability to engage in higher-order thinking. Prenatal exposure to toxins in the mother’s bloodstream affect both a child’s “cold,” or cognitive, executive functioning and their “hot,” or emotional/affective, functioning. Once again, children who are born with executive deficits may be more difficult around their caregivers. These children, who arguably need a close attachment relationship most, may miss out on the safety, comfort, and autonomy of a secure attachment bond.

            These studies highlight the close and subtle relationship between the prenatal environment, an infant’s stress response and executive functioning, and the child’s ability to develop an attachment relationship with its mother or caregiver. When thinking about interventions, neuroplasticity reminds us that nothing is set in stone. A high-stress prenatal environment can be counteracted by later experiences of attachment and connection. The “experience-expectant” parts of our brains, which develop tremendously over just nine months of pregnancy, can be countered by “experience-dependent” development (Sheridan & Nelson, 2009).

            From conception to childbirth to adolescence, parents must be reminded that they are always capable of influencing their child’s life and moving their infant toward a positive developmental trajectory. As health care professionals, it is our responsibility to remind parents of their power and guide them toward making smart, healthy decisions for both them and their children.

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References:

Davis, E. P., & Sandman, C. A. (2010). The timing of prenatal exposure to maternal cortisol and psychosocial stress is associated with human infant cognitive development. Child Development, 81(1), 131-148.

Sheridan, M., & Nelson, C. (2009). Neurobiology of fetal and infant development: Implications for infant mental health. In C.H. Zeanah (Ed.), Handbook infant mental health (3rd ed., pp. 40-58).  New York, NY: The Guilford Press.

Vaughn, M. G., DeLisi, M., & Matto, H. C. (2014). Human behavior: A cell to society approach. Hoboken: N.J.: John Wiley & Sons, Inc. 

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