What ‘Mommy Brain’ Really Looks Like

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Collage: Stevie Remsberg

NEW MOM explores the brilliant, terrible, wonderful, confusing realities of first-time motherhood. It’s for anybody who wants to be a new mom, is a new mom, was a new mom, or wants really good reasons to never be a new mom.

Perhaps one of the most dreaded aspects of new parenthood is the fearsome “mommy brain,” or the idea that a woman’s brain essentially melts into mush as soon as she’s had a baby. Common symptoms are said to include memory loss, confusion, and generally feeling a little, well, dumber than usual.

But science doesn’t support the notion that a woman’s brain becomes somehow impaired or weakened by giving birth; in fact, the research seems to show the opposite. We spoke to Dr. Pilyoung Kim, an associate professor of psychology at the University of Denver who’s studied the brains of moms in the months after they give birth, to learn more.

Where does this idea of “mommy brain” as confused and forgetful come from?
I mean, you know, there are major factors like sleep deprivation — that can be why new moms might feel like they can’t remember things, like where they put their keys, or things like that. But from the neuroscience perspective, what we see is that some parts of her brain actually grow [after she gives birth], specifically to support her new role as parent. We observed significant structural growth in several brain regions, including the midbrain region, which plays an important role in developing what we call “maternal instinct,” and the prefrontal cortex region, which is involved in decision making, learning, and regulating our feeling and thoughts, over the first three to four months of motherhood.

Does that mean other areas have to shrink, or…?
Our brain probably does have a limit on how many resources it has. And for a few months after having a baby, the most important task for the mom is to take care of her baby. So her brain seems to be undergoing pretty dynamic changes to support her in doing that role really well — that means taking care of her baby, building a really strong emotional bond with her baby. And a lot of her efforts and resources, and her brain’s resources, go into that part of her life. So, you know, there might be some other things that she was really good at before that may not be at the same level for a while (like remembering things, for instance).

So it’s like your brain is basically re-prioritizing for you.
When we look at several studies we’ve done on this, both structurally and functionally, the brain undergoes changes to form a very strong bias (for the mom) to notice her baby, and feel motivation to take care of the baby. There could be many, many different priorities in a mother’s life, but her brain seems to support her particularly for the parenting role.

For example, if she hears her baby cry, it’s very hard to ignore and continue to do what she was doing, right? We have this very strong urge to go and check on the baby and console the baby. That strong motivation is supported by brain activation. So when we present the sound of a baby crying to her mom, we can see which brain areas light up or become active during that period of time. Among many, many regions that we see, we see a very strong response in the brain region we call the reward circuit, which is the circuit that responds to many other things that are pleasant and rewarding, like food or sex. In mothers, though, the thing that activates this brain region most strongly are the baby cues. So listening to her baby cry, seeing her baby smiling, really strongly activates this brain circuit more than, probably, many other things that were previously very rewarding in her life.

I saw it mentioned in your research that this is one of the only way that an adult’s brain volume would increase in adulthood, apart from a traumatic injury or other health conditions. Is that right?
Adults’ brains have plasticity, meaning that they can go through changes, but seeing those changes in the number of areas we report in the paper is really rare. Parenting seems to be one of those adulthood experiences that are related to structural changes in a wide range of areas in the brain.

What are the benefits of these brain changes for the baby (beyond, like, staying alive)?
So, what see as researchers, especially during this early postpartum period — about the first six months after the baby was born — it’s a very special time for establishing that strong emotional bond with the baby. So during this period of time, a lot of mothers tend to spend quite intensive amounts of time with their babies. So that amount of interaction also supports the mom’s brain to develop very strong responses to her own baby, which include those structural changes. And then that strong emotional bond really helps develop that relationship with her child. For parents and children to have a long-term, positive relationship, we think that the first few months might be one of the really critical periods for the parents’ biological and psychological adaptation to parenthood.

What ‘Mommy Brain’ Really Looks Like