By Colleen Doyle
What makes us who we are? Historically, great debate has surrounded this question. Some have said it’s the genes we inherit at conception. Others have pointed to the environment we experience in childhood. Today, there is growing evidence that many of our individual characteristics—including our temperaments, our intelligence, and our mental and physical health—may be influenced by the interplay of our genes and the prenatal environment that we experience before birth. The goal of our new WISHES study (the Women and Infants Study of Health, Emotions, and Stress) is to learn more about how women’s experiences during pregnancy may “get under the skin” of their developing children to influence their brain development, behavior, and health.
Why are we studying prenatal experiences? All women experience some amount of stress and mood swings during pregnancy. However, a growing body of research has linked different levels of these “prenatal stress” experiences to both positive and negative outcomes for women and their developing children. For example, mild levels of prenatal stress have been linked to enhanced motor and cognitive development in infancy. In contrast, more intense or chronic experiences of prenatal stress have been associated with increased risk for an earlier birth, as well as problems with learning and controlling emotions during childhood. The mechanisms that link women’s experiences during pregnancy to long-term child outcomes are complicated and not completely understood. The goal of the WISHES study is to increase our understanding in this area. We think our study has the potential to make important contributions to how parents, pediatricians, and policy makers can help set up lifelong trajectories of health and well-being by supporting women’s health during pregnancy.
What is prenatal stress? Prenatal stress is a complex umbrella term that encompasses many experiences – from frustration with daily hassles, to mental health concerns related to anxiety or depression, to life circumstances that are difficult or impossible for women to control, such as significant financial concerns, the death of a loved one, or a disaster like flooding.
Additionally, a woman’s perception of whether something is stressful contributes to how she may experience prenatal stress. This means factors like a woman’s personality, her outlook on life, and whether she views her world as safe or unsafe can come into play.
Finally, prenatal stress is not exclusive to the prenatal period. Research shows that women who report feeling stressed, anxious, or depressed during pregnancy also report feeling this way through at least the first two years of their child’s life. This is important to remember, because this means there are potentially many opportunities to support women and their children.
Although the “prenatal stress recipe” can be different for every woman, we might think about the ingredients as being the sort of things that drive us “N.U.T.S.”, in that these things are Novel, Unpredictable, Threatening to our survival or our sense of self, and they foster a Sense of lacking control. This acronym isn’t meant to make light of prenatal stress, but rather to help us remember that prenatal stress occurs when a woman has more things coming at her than she can manage.
How does prenatal stress influence child development? Recent research suggests that experiences of prenatal stress might influence child outcomes by impacting brain development before birth. What we are learning is that prenatal stress can affect a woman’s health during pregnancy in two ways, which in turn can influence her child’s development. First, prenatal stress can affect behaviors that are important to maintaining good health during pregnancy (e.g., getting enough sleep, eating right, exercising, and getting good prenatal care). Second, prenatal stress can affect a woman’s biological functioning during pregnancy, including her hormones, blood pressure, and immune system. The placenta, which regulates the prenatal environment, likely plays a major role here.
What’s involved in the WISHES study? So far, we have very strong evidence from animal research that supports the hypothesis that prenatal stress influences offspring brain development before birth. To study this question in humans, the WISHES study is following women and their children from early in pregnancy through the first two years of life. Women enroll in the study between 8-12 weeks of pregnancy, and complete questionnaires on stress, emotions, and health behaviors 5 times during pregnancy. At 4 time points during pregnancy, women also complete fetal monitoring sessions, which involve placing electrodes on the woman’s belly to measure her baby’s resting heart rate. We look at fetal heart rate because it is a “downstream” marker of fetal brain maturation; as central nervous system development unfolds during pregnancy the brain increasingly controls the heart, and in turn resting heart rate patterns show expected patterns of organization and change. Therefore, by measuring changes in resting fetal heart rate during pregnancy we are able to understand how prenatal experiences may play a role in setting up different trajectories of brain development. At 3 time points during pregnancy, women also provide a small hair sample, which allows us to measure cortisol production during pregnancy. Cortisol is a hormone that helps our body cope and respond in challenging situations. During pregnancy, cortisol also helps mature fetal tissues, such as the lungs, and may impact the development of the central nervous system and brain. Finally, at 1 time point women complete a short computer game while we track their eye-movements, in order to understand how differences in attentional styles may play a role in whether or how women experience stress during pregnancy.
Following delivery, at 3, 6, 9, 12, and 24 months, children complete behavioral assessments and MRI brain scans, and parents complete questionnaires on their own experiences and their child’s development. We use MRI for this study because unlike other imaging methods it does not involve any radiation, making it completely safe for use with infants. Also, all scans are conducted in the evenings during children’s natural sleep, without the use of any sedation. Finally, a staff member is in the scanner with the child throughout the scan, so the scan can be discontinued immediately when children wake up.
Join us for the WISHES study. Every day we are learning more about how experiences during pregnancy may play a role in a child’s growth and development. However, we have much more to learn. This WISHES study will be the first to connect the dots between prenatal experiences, brain development across pregnancy, and brain and behavioral development during the first two years of life. This will allow us to significantly advance our understanding of how prenatal experiences may play a role in setting up different trajectories of brain and behavioral development.
Women and families will be compensated up to $560 for participating and will receive a small gift featuring pictures of their child’s brain. For many of the prenatal visits we are able to meet with women at their homes. For all visits held at the U of M, we provide free parking and child care for older siblings. For more information on the study please email us at doyle291@umn.edu.
