Maternal Stress & Fetal Effects

Pregnancy, for many women, is a time of happiness and anticipated changes. However, even if a woman welcomes these changes, pregnancy can add new stressors to her life. Stress occurs when an individual’s external demands exceed the adaptive capacity of that individual.¹ Stressors are different for every individual. Nausea, extreme fatigue, or mood swings are some of the common stressors that can make pregnancy difficult to manage. Psychological stress also has a role in affecting the mother and her fetus. Stress resulting from job responsibilities, separation from a significant other, and death of a family member or friend can lead to complications for a woman and the fetus. Women also may have the tendency to stress about miscarriage, fetal health and development, future labor, or their new role as a parent. These complications from maternal stress can affect the fetus while in utero and the newborn post-delivery.²

Current Research
In past research, it was believed that a fetus was conceived with a blueprint from their parents’ genes and as long as the growing fetus received the appropriate amount of nutrients and harmful substances were avoided maternally; this blueprint would produce a healthy newborn.³ This past research is no longer credible. According to Federenko & Wadhwa, the fetus utilizes cues from its external environment to determine the most suitable process to construct itself within the genes parameters.⁴ Furthermore, this current research suggests that a fetus is affected by the mother’s emotional and physical health, and these conditions may have a more significant impact on the fetus than the genes it inherits. Conditions in the uterus such as hormones and nutrients supplied from the placenta can affect the function of an infant’s liver, kidneys, lungs, heart and brain function during childhood and adulthood.⁴ Maternal stress and anxiety has been associated with shorter gestation and a higher incidence of preterm birth, lowered birth weights and lengths, and an increased risk of miscarriage. Preterm infants are more susceptible to a range of chronic complications such as: lung disease, developmental delays and learning disabilities. Preterm infants also may be more susceptible to mortality. More compelling research has proven that infants experiencing stress in utero are more prone to develop chronic health conditions similar to adults such as heart disease, hypertension, and diabetes.³

Some studies are suggesting that stress in the womb can affect an infant’s behavioral and emotional response. Fetuses that were exposed to high levels of stress, particularly within the first trimester, tend to exhibit greater signs of irritability and depression in life and well as lower IQ scores.⁴ Infants exposed to maternal stress and anxiety also tend to be more fussy and difficult to soothe.⁴ There have also been several studies linking adverse intrauterine conditions and an increased risk of developing ADHD.⁵ Even more captivating is the study published in 2008 at Harvard Medical School.⁶ This study was the first of its kind to identify a link between prenatal stress and anxiety to future allergy and asthma in infants. Researchers at Harvard suggest that even with low allergen exposure in the home, the fetus’ immune system becomes compromised and the risk of developing allergies and asthma after birth increases if a mother is stressed or anxious during pregnancy.⁶

Hormones Involved
Researchers are not positive which responses play a huge role in maternal stress, but it is clear that a woman’s body and brain produces a series of chemical changes such as the release of adrenaline and cortisol. Commonly, these chemicals are good and help prepare an individual’s fight or flight response. Hormones in the appropriate amounts are essential for preparation of life outside of the womb. Prolonged exposure to these hormones, however, can cause damage to the expectant mother and her unborn fetus. In the instance of a pregnant woman, epinephrine and norepinephrine are stress hormones that can constrict blood vessels and reduce oxygen to the uterus, making it difficult to transport nutrients to the developing fetus from the placenta which in turn can affect the developing fetus’s organs. Another hormone that is released with higher stress levels is the corticotrophin-releasing hormone (CRH). This hormone sends messages to the pituitary gland to make cortisol. An excessive amount of cortisol can suppress the immune system (increasing the risk of infection), increase sugar levels in the blood and increase blood pressure.⁷ The fetus in utero is exposed to these stress hormones released maternally and exposure to unhealthy levels can impact the fetus’ brain development and future health.⁸

Decreasing Maternal Stress
Several factors can accomplish a decrease in maternal stress such as: educating women about the potential affects stress can have on a developing fetus. As nurses we can educate expectant mothers about simple modifications they can make to decrease stress and anxiety such as:

• Knowing or increasing awareness of their personal stressor
• Avoiding people, situations, or things that cause them stress
• Develop and surround themselves with a strong support system
• Consistent prenatal care
• Participating in exercise such as guided imagery, walking, or yoga
• Engaging in light exercise which can help their body to produce endorphins and counteract stress and anxiety effects
• Adequate rest, consumption of a healthy diet, and avoidance of alcohol and recreational drugs

Some of the personality traits that account for some women coping with stress more so than others include: optimism, self-esteem, feelings of self-control, and expression of emotion.⁹

Nurses, midwives, and other healthcare professional that resume care of pregnant women will benefit from this literature review. The utilization of the above relaxation techniques can be beneficial to healthcare professionals when used to educate and encourage future or expectant mothers in the clinic setting to maintain a healthy lifestyle.

Erika Lugo has been a nurse for 13 years and has worked in many specialty areas such as Peds, NICU, Rehab, High Risk OB and Mother/Baby.

References
1. Lau, Y. The Effects of maternal stress and health-related quality of life on birth outcomes among Macao Chinese pregnant women. Journal of Perinatal and Neonatal Nursing. 2013;27(1):14-2
2. Stress and Pregnancy: March of Dimes. 2012. http://www.marchofdimes.com/pregnancy/stress-and-pregnancy.aspx.
3. Fetus to Mom: You’re stressing Me Out! 2000. http://www.webmd.com/baby/features/fetal-stress.
4. Federenko IS, Wadhwa PD. Women’s mental health during pregnancy influences fetal and infant developmental and health outcomes. CNS Spectr. 2004;9:198-206.
5. Buss C, et al. Impaired executive function mediates the association between maternal pre-pregnancy body mass index and child ADHD symptoms. PLoS ONE. 2012;7(6):e37758.
6. South Asian Emotion: The effects of prenatal stress on fetal development. 2011. http://www.mysahana.org/2011/02/prenatal-stress-fetal-development.
7. Adrenaline, Cortisol, Norepinephrine: The three major stress hormones explained. 2013. http://www.huffingtonpost.com/2013/04/19/adrenaline-cortisol-stress-hormones.
8. Di Pietro JA. The Role of Maternal Stress in Child Development. Current Directions in Psychological Science. 2004;13(2):71-74.
9. Wadhwa PD. Psychoneuroendocrine processes in human pregnancy influence fetal development and health. Psychoneuroendocrinology. 2005;30:725-743.