Local researchers break new ground on prenatal stress

By Sam Leishman - Lethbridge Herald Local Journalism Initiative Reporter on March 13, 2025.

New research from the University of Lethbridge could revolutionize how we think about the effects of stress on pregnant moms and their babies.
Stephanie King, the lead author of the study, and Gerlinde Metz recently joined a team of researchers to examine the consequences of prenatal maternal stress (PNMS) on four generations of rat offspring, building upon previous research into the same topic. PNMS is described by King as any kind of overwhelming experience for the expecting mother, including but not limited to abuse, neglect and poverty.
During her time as a post-secondary student, King says she was fascinated by the role that adverse childhood experiences and early life stress play in the development of adulthood diseases, which later inspired this study.
“Something that you had zero control over can impact your health,” King explains. “If your mom is pregnant with you and then she experiences something that’s really impactful, that can then impact the developing fetus which then impacts that future child and that future adult. What your grandmother experienced could theoretically impact you, too.”
The researchers found that the first and second generation mother rats who experienced some form of PNMS had shorter pregnancies than usual and showed similar symptoms to anxiety and depression. Their pups also had reduced weights at birth and delayed sensorimotor development.
As described by a 2023 article published by the National Library of Medicine in the United States, sensorimotor development in humans is a period between newborn and about two years old when children use their senses and motor skills to learn about cause-and-effect relationships and the environment around them. For example, a healthy toddler will eventually understand that shaking a rattle produces sound.
“We found that the first generation of offspring revealed a moderate impact of PNMS, but we saw drastic changes in the second and third generations,” says Metz.
The placenta was a key area for examination in this study. King says it could potentially hold the answer for why some non-genetic conditions, like obesity, anxiety, depression, and respiratory and kidney diseases, are passed down through families.
The placenta typically shields the fetus from the mother’s stress hormones, according to King. However, if significant enough stress happens at a critical point in the pregnancy, it could affect the eggs and sperm, and possibly cause health complications for several future generations.
King says more animal testing over a greater length of time is the next step.
“I think looking throughout the pregnancy to see individual changes in the placenta versus the brain would be very helpful. One thing would be to eventually see if there’s changes in the placenta that correlate with changes in the behaviour or health of young infants, and eventually toddlers and teenagers.”
When it comes to mitigating the effects of PNMS, King says it’s important to surround expecting moms with quality social supports, including loving family and friend relationships, enjoyable hobbies, financial stability and a reduced workload.
She adds that this research could result in earlier health screening and more thorough treatment, as well.
“We could see proof that the placenta could be a window into what’s going on neurologically with people,” King told the Herald. “It’s so much easier to intervene before something starts than it is to treat something once it has already started. The dream in medicine is prevention and personalization.”
King is currently working as an assistant professor and research director at St. Matthews University School of Medicine in the Cayman Islands.

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