Why ‘Mommy Brain’ Is Actually Your Secret Weapon

When my youngest was still an infant, I pulled out of my driveway with my coffee and purse bouncing on the rooftop of my SUV. Classic. When I finally realized and pulled over, a passer-by commented on my “mommy brain.” He thought he was so clever, and I smiled—he was right, but I wasn’t crazy about his condescending air of judgment.

Now as a psychologist who works with pregnant and newly minted mothers, I often hear about “mommy brain” and the decline in cognitive functioning, especially memory and attention, for pregnant and postpartum women. These incidents often evoke tears in the moment and then, more often than not, morph into the humorous memories that are laughed at in retrospect. At ladies’ nights, these shared stories function as hard-earned badges of motherhood: concrete and real examples of all that mothers give up physically, emotionally, and cognitively.

Research tells us that mothers’ brains shrink during pregnancy and for up to two years postpartum. Article after article cites the realness of mommy brain—because yes, of course you would expect that surging hormones, sleep deprivation, and caretaking for another human dependent on you for their survival would shift things a bit. But until recently, post-pregnancy brain changes were not well-understood.

Recently, it was discovered that gray matter—the outer layer of the brain responsible for social cognition—decreases in size after pregnancy. At first, that might seem paradoxical. A loss of brain function? But what is really happening is that the brain is trimming away the less important neural information to clear space for the increasing demands of social connection. This process is called “synaptic pruning” and allows the mother to develop a deeper and more responsive connection to her baby, increasing maternal bonding.

Imagine you have a plant with gorgeous flowers that are lost in an overgrowth of weeds, bush, and other debris. Pruning the bed allows you to display the most beautiful flowers by cutting back the overgrowth to create space. You invest in the flowers you love and cut the ones you don’t, allowing your favorites to receive the most water, sun, and nutrients. This is how you produce a thriving garden, much like growing a thriving brain.

Pruning of gray matter is similar. The most important connections are strengthened while the less important are left to fade. Instead of losing cognitive capability after pregnancy, the brain is actually strengthening and specializing in the most valuable way: social connection. A similar change occurs in early childhood and during adolescence to boys and girls to improve cognition. The brain cleans house, working to rid itself of less useful connections while carrying the most important to maturity. Smart, right?

“Mommy brain” is often thought of as something to hide so people don’t think less of you. Kim Larsson, Ph.D., R.N., C.S., encourages mothers to focus on the “shifting brain” growing in new ways to adapt to new challenges. In some ways, you are working with new tools that must be understood by you first. Unfortunately, our partners and co-workers might not realize this and only notice the obvious screw-ups.

So take the time to process how you have changed, embrace it, and view it with awe and appreciation. Once you can see the value yourself, share it with others. Trim back the focus on the losses to see the beauty of the gains. Next time you put your keys in the fridge, hold your head high and consider yourself a highly specialized social expert. Keys on the counter or keys in the fridge doesn’t really matter anyway. You are a social beast.

Here are a few things to keep in mind about “mommy brain” going forward:

Brains post-pregnancy trim the less useful information and invest in the most important information. This is called “synaptic pruning” and explains why you feel so connected but sometimes forget meaningless information (your ex-colleague’s name).