This article is authored by Braden Lang and Danny Rahal.
It is well established how influential parents are on their children’s development. A decision to immigrate to a new country or the levels of substance use during pregnancy can drastically alter the course of a child’s life. But just how early can a parent shape the outcomes in their children? Recent research suggests that the mental health of mothers before pregnancy can impact their child’s physical health.
The researchers recruited 85 mothers who had recently given birth to a child as part of a longitudinal study. They interviewed them in 6-month intervals until their next pregnancy, assessing PTSD and depression symptoms as well as perceptions of stress. The sample of mothers was racially diverse (11.76% African American, 25% white, 49% Hispanic, and 8% were multiracial), completed high school on average with some college graduates, and were well above the federal poverty line. The children born of the subsequent pregnancy had their diurnal rhythm and CAR measured at age 4- and 5-years-old. Results were then analyzed in relation to their mother’s mental health data to determine if there was any relationship between the two.
So, win the world is a diurnal slope of cortisol? Diurnal means of or during the daylight hours. Cortisol is a hormone secreted by the adrenal glands whose primary function is to mobilize energy. Levels of cortisol usually rise in response to a stressor, earning the nickname the “stress” hormone. Importantly, stressors are not limited to physical triggers. Yes, running for your life is bound to impact how much cortisol is being released but so will psychological stressors like ruminating over uncontrollable events or experiencing racism. When levels of cortisol are chronically elevated or there is an increased risk for health problems you don’t want, like hypertension, atherosclerosis, and ulcers.
But you need cortisol. It is being constantly pumped out by your body, not just in response to a stressor. Remember, its primary function is to get your body the energy it needs. Because of this, cortisol levels peak about 30 minutes after waking and drop throughout the day. To measure diurnal slope, cortisol measurements must be taken at at least three points, upon waking, 30 minutes after waking up, and when going to bed. The CAR (cortisol awakening response) is measured by comparing the differences between cortisol levels at wake and about 30 minutes after wake. So, say you measured your own diurnal slope and are wondering what’s a “good” value for it. In general, steeper slopes of diurnal rhythm (meaning the greater amount of change from the 30 min peak to the bedtime trough) are associated with better health outcomes. A healthy CAR is a moderate and consistent one. Too high of a CAR on a given day is associated with increased feelings of stress and too low indicates failure to mobilize energy and is related to feelings of burnout and PTSD symptoms.
A consistent CAR is generally a healthy one as this indicates a sustainable routine. A “high” or “low” CAR largely depends on the person. Taken together, cortisol is secreted in response to a stressor, but chronically high or chronically low levels of it can disrupt your health.
Now that we’ve covered cortisol, let’s go back to what the study found. Maternal PTSD symptoms prior to pregnancy were associated with a shallower cortisol diurnal slope for children at age 4. The families were followed up at age 5, and results suggested that PTSD symptoms were similarly related to a blunted cortisol diurnal slope at that age. To note, there was no association with maternal depressive symptoms and perceived stress on diurnal slope. Additionally, children’s CAR at ages 4 and 5 had no significant association with any markers of maternal mental health.
So, what does this mean? It appears that the prenatal environment has been proved to be a powerful influence on the development of cortisol in infants, children, and adults. Should you be panicked that your stress now will affect any children you have in the future? Not necessarily. To start, the observed effects were significant but very small. Just because a mother is experiencing high levels of distress prior to pregnancy or even during pregnancy does not doom their child to a life of poor health. After adjusting for other factors, PTSD symptoms were no longer significantly associated with a child’s diurnal slope at age 5.
The exact mechanism that may be responsible for how pre pregnancy influences offspring development is unknown. Many hypothesize epigenetic effects, changes in the uterus, or alterations of sex cells could be involved. It also may be that a mother’s mental pathology symptoms before pregnancy could influence their parenting style.
All in all, this research allows for new explanations of diurnal slope variability in children and accomplished this through robust methods of mental health, biology, and demographic analysis. Although the significant effects of the study were small, they are incredibly relevant. Small effects can accumulate over time—showing differences in cortisol levels could affect children’s daily energy levels and even immune system activity. If poor mental health before conception can influence cortisol regulation by age 4, it’s likely that other subtle factors are shaping who we become. Although biological factors from pre-pregnancy may affect children’s health, scaffolding enriching environments for children and having early targeted interventions could counteract these effects and benefit future generations of youth.
References
- Guardino, C. M., Rahal, D., Rinne, G. R., Mahrer, N. E., Davis, E. P., Adam, E. K., Shalowitz, M. U., Ramey, S. L., & Schetter, C. D. (2022). Maternal stress and mental health before pregnancy and offspring diurnal cortisol in early childhood. Developmental Psychobiology, 64(7). https://doi.org/10.1002/dev.22314