May 9, 2014 11:37 am

Mother’s Day: How motherhood changes a woman’s brain

Eight-week-old Eleanor Delp attends a 'What to Expect' baby shower with her mother August 21, 2012 in Springfield, Virginia.

Alex Wong/Getty Images

TORONTO — She’s laser-focused, with a set of sharpened senses and an enhanced ability to learn and get the job done. She’s a new mom and now that she’s looking out for two, her brain has made way for a series of changes that’ll help her in the life-long job she’s taken on.

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Dr. Craig Kinsley saw it in his wife: once she learned she was having the couple’s first child, the neuroscientist’s partner Nancy sprung into action, “gathering provisions” as he called it. Before her pregnancy, Nancy was ambivalent when it came to kids. By the time their daughter was born, she was happily juggling her everyday duties along with her new responsibility of looking after another human being.

“Her behaviour just became much more efficient. She did all of those things she was doing before plus behaviours in keeping baby happy and healthy all in the same time frame,” Kinsley, of the University of Richmond, said.

“She didn’t have more time, she just knew what to do.”

READ MORE: Newborn baby’s smell is as addictive as drugs or food, study says

To mark Mother’s Day, Global News talked to leading scientists studying just how pregnancy and motherhood changes a woman’s health, not just physically but mentally. Research has suggested that they have innate hearing, a refined ability to multitask and a protective nature that kicks aside any doubt. A mother can recognize her baby’s distinctive cry, is addicted to his smell and she knows how to answer to his needs, the doctors say.

A ‘profound’ bond

“The relationship that a mother develops with her infant is one of the most profound influences in a child’s life and has the most long-lasting effects,” according to Dr. Lane Strathearn, a developmental pediatrician at the Baylor College of Medicine.

“Women have to sacrifice much to give the time and attention needed by their children but by doing so, they develop skills that you can’t develop any other way. So it’s a two-way experience,” he said.

Strathearn even posits that motherhood may be one of the handful of times in a female’s lifetime that she’d undergo such rapid growth to her brain next to infancy and adolescence.

READ MORE: New moms, lose baby weight or face diabetes, heart health risk

It begins with the feel-good chemicals. Strathearn recruits new moms during pregnancy and follows them shortly after their babies are born. He examined his study participants’ interaction with their babies and analyzed their brain response, particularly when their children cry or smile.

When she sees her baby smiling and laughing, a mother’s brain’s reward centre is flooded with feel-good chemicals.

The oxytocin, dubbed the “cuddle hormone,” starts flowing into her system as early as in the pregnancy stages, Strathearn found. Women also get doses of dopamine, the reward hormone.

“It helps prepare a woman for this major change in what’s happening so she can be more responsive to cues and have an innate ability to respond to her infant’s needs,” Strathearn said.

READ MORE: Do babies inherit junk food addictions from their moms?

It’s like falling in love

When Dr. Pilyoung Kim had her son, she was hooked. The University of Denver developmental neuroscientist, who has spent a decade in this field of study, compares motherhood to falling in love.

It was like an obsession — she was constantly checking on her son, she’d forgo eating and sleeping to put his basic needs first, and his laugh and his cry elicited an instant response from her. Sound familiar, moms?

“If you’re falling in love, that’s all you think about: the other person day and night. I always want to know what the person is doing so it’s kind of like a similar experience but it’s even more intense,” Kim explained.

Kim’s sentiments should come as no surprise: both dopamine and oxytocin are key factors in the neurochemistry of love.

When a mother breastfeeds, for example, she’s flooded with oxytocin that reinforces her love and bond with her baby.

Kim’s own research into the matter suggests that reward regions of the brain increase in size, especially to make room for these feelings that promote bonding and feeling motivated to look after her baby.

The more a mom cooed over her baby — “how perfect, how beautiful,” Kim explained — the more the increase in brain size was documented, according to Kim.

READ MORE: What older moms and teenage pregnancy say about opportunity in Ontario

She pointed to research that had rats choose between access to cocaine or seeing their pups. Time and time again, the rats with babies turned down the highly addictive drugs to see their pups, and the experience was far more rewarding to them, Kim said.

“It shows that the same reward circuits become more specific and highly sensitive to infants,” she told Global News.

The brave, quick-thinking, multi-tasking mommy

Kinsley’s been studying motherhood and its effect on women for a near quarter century, but he concedes, “I’ve been trying to understand the female brain since puberty.”

In his lab, research has suggested that there’s a “huge” disparity between how mother rats and virgin rats perform in foraging. The scientists had the rats forage in an unfamiliar maze.

Rats with mouths to feed were much better at remembering locations of food and water. (In other research, rat moms were better at remembering patterns to get to their food reward than their virgin counterparts.)

READ MORE: How a father’s diet, lifestyle affect his baby’s healthy development

Kinsley said that moms are left with a dilemma: stay in the nest, protect your kin and keep them warm or look for food so they don’t starve but at the risk of exposing the babies to danger. So when she leaves them behind, she makes every second count.

“The only thing that makes sense is to forage more efficiently so she has an enhanced learning ability, spatial ability and she’s prepared to defend herself against predators,” Kinsley explained. They’re also much more aggressive than virgin rats — mother rats, although a third larger, were more adept at catching prey compared to their nimble, young counterparts.

“They’re bolder, stronger and smarter and it comes together to help them take care of their babies,” he said.

Kinsley suggests that Canadians should rethink the mother-baby bond, too. We often see it as infants helplessly relying on their moms, but they deserve more credit.

“The baby is producing sights, smells, sounds and stimulation — all of these effects that feed back on a mom’s brain to keep her focus back on the infant,” Kinsley explained.

“They’re not just lying there passively, they’re creating a means so their mother exerts better behaviour towards them. It’s literally keeping the [mother's] brain young.”

Watch: UBC neuroscientist Liisa Galea discusses ‘baby brain’ and other ways that motherhood changes a woman’s brain chemistry.

carmen.chai@globalnews.ca

© Shaw Media, 2014

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