Parenting isn’t exactly a low-stress job. In fact, anxiety is more likely to arise now than ever. New mothers especially have to learn how to deal with new stressors when raising a baby for the first time – so we have to wonder, how does stress affect the way new mothers parent?
In a new study published in PsychoneuroendocrinologyResearchers found that high levels of cortisol in new mothers were associated with greater intrusive parenting behaviors and reduced activation of motor planning and auditory processing areas of the brain in response to infant cries.
Basically, stressed mothers were less likely to let their babies guide their play and were less responsive to their babies’ cries.
Well, that’s all. Let’s start from the beginning.
Cortisol is often called the “stress hormone” and naturally fluctuates throughout the day. It plays many important roles in the body, such as regulating immune function and anti-inflammatory mechanisms, and determining our fight or flight response.
Stress can cause cortisol levels to rise, but they tend to return to normal quickly. (While you may see this on TikTok, high cortisol levels (a symptom of Cushing’s syndrome) are fairly rare, and health baselines can vary from person to person).
However, according to the study, high basal cortisol levels were associated with less engaged parenting behaviors. Researchers have previously shown that higher basal cortisol levels are associated with less sensitive and more intrusive caregiving behaviors in mothers of infants aged 3-6 months.
“Maternal intrusiveness refers to the degree to which a mother follows her child’s lead and waits for an uninterrupted entry point into the interaction,” the study explains.
The researchers’ goal was to find out how cortisol changes moms’ brain function and explain why and how this change translates into their parenting behaviors.
“The goal of this study was to understand how the multiple biological systems that underpin parenting behavior interact,” said study author Andrew Earhart. Earhart is a school-age systems specialist with the Colorado Department of Public Health and Environment and conducted the research while a member of the Family and Child Neuroscience Laboratory at the University of Denver.
“We know that the transition to parenthood is a critical period, with changes in the brain and body occurring to support the development of nurturing behaviors. I am particularly interested in understanding how environmental influences such as the postpartum environment and chronic stress modulate the transition to parenthood Biological changes in the process.
The study surveyed 59 first-time mothers with babies aged 3 to 4 months. The mothers participated in home and laboratory sessions, and researchers assessed their cortisol levels, behavior when interacting with their babies, and brain responses to their babies’ cries.
At home, the researchers observed interactions between mothers and babies without the use of toys. They then coded behaviors to increase sensitivity and non-intrusiveness to the infant’s cues. The researchers collected cortisol samples during treatment to determine the mothers’ average cortisol concentrations.
During laboratory sessions, mothers underwent functional magnetic resonance imaging (fMRI) scans. The researchers played recordings of the mothers’ own infants and a control group of infants crying. They then used functional magnetic resonance imaging scans to measure activity in different areas of the brain in response to the baby’s cries.
Home visits showed a clear link between mothers with higher cortisol levels or higher levels of stress and intrusive parenting.
Functional magnetic resonance imaging scans also showed that higher cortisol levels were associated with reduced brain activity in multiple areas of the brain in response to baby cries. Reduced brain activity has been linked to more intrusive parenting, leading researchers to conclude that mothers with higher cortisol levels may have a reduced ability to respond calmly and effectively to their distressed babies.
However, the researchers were surprised that the effects on the brain were more concentrated in the areas of motor planning and auditory processing than in the area of emotion regulation. Further research is needed to understand the link between brain function and behavior in this process.
“The point is, we have a better understanding of how our stress system interacts with the mother’s brain in response to infant crying and how that relates to parenting behavior,” Earhart said. “We know that the stress systems responsible for motor planning and Areas of the brain involved in auditory processing are less exposed to areas with higher cortisol concentrations.”
