Prenatal Stress Can Affect the Fetal and Infant Brain

By Nicole Letourneau and Justin Joschko

Prolonged exposure to toxic stress has been linked to depression, heart disease, diabetes and alcoholism

Last month, it was reported that an Edmonton woman was badly beaten by her spouse. Though the attack put her in the hospital, the police offered a silver lining by stating that her unborn baby, at least, wasn’t harmed.

Sadly, this claim underestimates the profound effect severe stress can have on children’s development in their first years of life, including while they’re still in the womb. In order to help end the cycles of violence that all too often lead to these situations, we must understand the full effects of abuse and neglect early in life – and what can be done to correct them.

Evidence shows that exposure to their mothers’ prenatal stress in consistently high doses– a state called “toxic stress” – affects fetal and infant brain architecture, placing the growing child at risk for numerous emotional and intellectual challenges. Exposed children have a harder time paying attention to instructions, and fare worse in puzzles and activities designed to measure cognitive ability. That's why it is so important to have as healthy and professional prenatal care as possible, or even to find an alternative prenatal way to help with stress, such as a prenatal massage. 

The main culprit in these cases is a stress hormone called cortisol. Though made naturally in our bodies and a key part of our stress response system, cortisol can be nasty stuff in large doses. Our glands produce it in times of real or perceived danger, where it shifts us into a kind of emergency mode: redistributing energy from our organs to our major muscle groups – the better to flee or fight with – and shutting down our immune and digestive systems to concentrate on the more immediate task of survival.

All of this is of great importance when fleeing from a tiger, or battling a warring tribe, or facing one of the other myriad dangers that plagued our distant ancestors. But in the face of extreme stress experienced by some people today, it can become a liability, as its presence prevents the body from returning to its pre-stressed state, called homeostasis.

Homeostasis is where our bodies function most optimally; if we lose the ability to downshift to this lower gear, the damage over the long term – the wear and tear, so to speak – can be considerable. Prolonged exposure to toxic stress has been linked to depression, heart disease, diabetes, and alcoholism – diseases we associate with adulthood, but whose seeds are often sown in the first years of our lives.

Fortunately, many effects of toxic stress can be mitigated. And the cure is not a matter of expensive pills or complex medical treatments. For parents, it’s a matter of support. Supporting parents – through women’s shelters, through tax relief, through better services for those with mental illness – we help two generations, parents and the next generation.

For children, it’s a matter of supporting parenting. The same study that reported an association between prenatal stress and lower cognitive abilities found that these problems were completely reversible, so long as children received consistent, loving attention from at least one caregiver. “Serve and return relationships,” characterized by responsive, helpful interactions between children and adults, have powerful healing effects.

Though the exact mechanisms aren’t well understood, we think that caring serve and return relationships with parents act a stress filtration system for their children, buffering them from the bursts of cortisol their young bodies aren’t yet equipped to handle. Healthy relationships may therefore recalibrate kids away from overproducing cortisol.

Support can make all the difference between a cycle of violence being repeated or broken.

If we want to end abuse, to eliminate poverty, to help solve the thorniest problems our society faces, the best place to begin is at the beginning: prenatal and infancy. And we can’t forget who raises those infants. We must support their parents, especially the ones most stressed. We all have a stake in protecting and supporting today’s parenting families to give all our children the best start.

Nicole Letourneau is an expert advisor with EvidenceNetwork.ca and a professor in the Faculties of Nursing and Medicine.  She also holds the Norlien/Alberta Children’s Hospital Foundation Chair in Parent-Infant Mental Health at the University of Calgary. 

Justin Joschko is a freelance writer currently residing in Ottawa. Their co-authored book, Scientific Parenting, has recently been released with Dundurn Press.