Before my son was born, I thought my life would simply continue as before, plus one. As I juggled caring for the baby and continuing to write, things soon began to slip. I misplaced the family car, missed deadlines, forgot an important radio interview. But rather than learning to cut back and say no, I used the excuse mentioned on all the parenting blogs—it wasn’t me, it was my “baby brain.”
Equating motherhood with forgetfulness and stupidity has a long history, dating back to the work of English paediatrician, psychoanalyst and author Donald Winnicott in the 1950s. Winnicott described the first few intense weeks of motherhood as “primary maternal preoccupation,” during which the woman is completely emotionally and physically consumed by her baby. The intensity of the early relationship was necessary, he argued, because the quality of maternal care determined the baby’s future, deciding his or her health, personality and emotional stability. Winnicott’s work was supposed to champion and support motherhood. But as it took hold, it was used to scrutinize the growing number of women entering the workforce from the 1960s onwards, and sometimes to provide scientific basis for the resentment that they were taking male jobs—while not actually having the mental capacity to focus on work outside the home.
A baby sapping a mother’s brain power hit a collective nerve, becoming a familiar cultural trope, epitomized in generations of television featuring ditzy moms. Meanwhile, social media has added its own #babybrain hashtag and memes, including cartoons of crazed-looking creatures lobotomizing themselves and dumping their brains in the trash, or those vintage-style illustrated e-cards with the message “I used to have functioning brain cells but I traded them in for children.” As the idea spread worldwide, it has gained its own regional varieties like “placenta brain” (Australia), “porridge brain” (UK), “pregnancy dementia” and “momnesia” (both North American).
But how much of this stereotype about a new mother’s cognitive difficulties is sexism, and how much is scientific fact? When Pulitzer prize-winning journalist Katherine Ellison had her first son, she heard other mothers complain that parts of their brains had been tossed along with the placenta. She decided to probe the myth by reviewing research and interviewing neuroscientists worldwide, including in Canada. The result was her book The Mommy Brain: How Motherhood Makes Us Smarter. Although the debate continues—and there is scientific evidence of temporary decline in certain parts of the brain—the connotations of the terms “baby brain” or “mommy brain” increasingly seem misleading, according to Ellison and the numerous studies she examined. Far from turning our brains to mush, motherhood can actually make women smarter, more resilient, less reactive and more focused.
“The practice of raising children can be a powerful learning mechanism that leads to major changes in your brain over time,” explains Ellison. “You exercise and deepen important skills including not only efficiency but ideally also emotional intelligence.”
Our enhanced ability to handle emotional stress facilitates many of these adaptations. To understand what is happening at a cellular level, Kelly Lambert, a neuroscientist in the department of psychology at the University of Richmond, looked at the brains of rats. Lambert found the rodent mums had less glucocorticoid stress hormones (which are toxic with chronic release) in their brains compared to the virgin females. Looking after a baby is incredibly taxing metabolically, she says, and “takes up a lot of mental real estate.” By increasing our ability to “streamline” stress, the mother becomes more focused on what really matters, i.e. keeping her baby healthy.
Stress is also mediated by a hormone called oxytocin, sometimes called the “cuddle hormone” or the “love hormone,” which floods the mother during childbirth and lactation. Studying the differences between lactating mothers and non-mothers, Kerstin Uvnäs-Moberg, professor emeritis of physiology at the Swedish University of Agriculture and author of Oxytocin: The Biological Guide to Motherhood, found the former were less reactive (lower cortisol and blood pressure) to the same levels of stress. Margaret Altemus, a professor of psychiatry at Yale School of Medicine, tested the stress of 20 healthy women in their twenties and thirties—10 lactating and 10 non—by requiring them to exercise on a treadmill. The lactating women released only half the stress hormones, she found, compared to those who were not nursing. By lowering cortisol levels, oxytocin improves body and mind: Higher levels of cortisol are linked to increases in blood pressure, cholesterol and heart disease risk. By consuming mental resources, stress also impairs brain ability.
“It’s a fantastic adaptation,” says Uvnäs-Moberg. “There are changes in memory. [With], she becomes much better able to remember people and social cues. She becomes more intuitive and sensitive. Oxytocin adapts the whole mother in an optimal way to be able not only to care for the baby but to be more social and less stressed.”
A mother’s brain changes in other ways too. The hippocampus—the part of the brain associated with spatial awareness and memory—temporarily shrinks during late pregnancy and early motherhood. Many other parts of the brain gain new grey matter, according to research done by James Swain, a professor at the Yale School of Medicine. He conducted MRI brain scans of human mothers and non-mums. Between two and four months postpartum, mothers’ brains increased their neuron-containing grey matter in the prefrontal cortex (the part of the brain used for complex cognitive processes, including thinking, planning and decision-making), the amygdala (the part of the brain used to respond with and store emotions), and the hypothalamus (the part of the brain that controls the physiological functions, such as reactions of the central nervous system).
Rutgers behavioural neuroscientist and professor of psychology Tracey Shors hypothesizes that this is nature’s way of making sure that mothers have enough brain power to keep their young ones alive. “You think you are ready to become a mom, you go to Lamaze classes, and you read all of these books, but when you are really confronted with it, you have to bear down and pay attention. Your brain pretty much has to reorganize on the spot.”
The brain isn’t static, but changes in size and shape according to what you do with it. This is called neuroplasticity. So, for anyone involved in the endless multi-tasking of childrearing—from figuring out feeding and sleep schedules to the endless coordinating of doctor’s appointments and playdates, all the while still trying to perform other work and take care of yourself—you gain grey matter in the areas of the brain associated with emotion regulation, conflict management, working memory and focus, according to a 2010 study in the journal Behavioral Neuroscience.
But this isn’t the only reason for how and why brains change. The latest science of epigenics says that a chemical switching system turns genes on and off throughout a lifetime in response to one’s environment and experience. During pregnancy, birth and breastfeeding, the mother’s body is flooded with oxytocin, vasopressin, estrogen and progesterone to help her cope. These chemicals affect the brain’s neurotransmitters, which regulate the activity of genes, causing long-term changes, explains Cort Pedersen, a professor of psychiatry and neurobiology at the University of North Carolina. “The chemical balance in the brain is altered for a sustained period. That affects the neurotransmitters which influence how easily some genes are expressed. Females that have become mothers are smarter. They learn better and remember better.”
And yet, the prejudice remains. Sleep deprivation is an important factor: According to James B. Maas, an author and international consultant on sleep and performance, the primary caregiver is estimated to lose up to 700 hours of sleep during the first year of the baby’s life. And there’s the phenomenon called “stereotype threat,” adds Ellison. It means that, if you think motherhood is making you stupid, you are more likely to remember those times when you forgot an important radio interview and overlook all those times when you managed to bake a birthday cake while simultaneously breastfeeding and answering dozens of work emails.
“Being a mother and learning how to be a good one takes lots of mental and physical energy,” explains Shors. “I would call it a ‘desirable difficulty.’ It seems hard in the moment, but it is the best way to use our brains. We are made for this."