Happy couple with pregnant wife

So much goes into being a good parent. Expectant mothers and fathers read books, take courses, and seek advice from trusted friends and family to prepare for the role of a lifetime. But the truth is, a lot of parenting is biological. Our bodies have evolved over centuries of human history to help us succeed at raising happy, healthy offspring. In this article, we take a look at how the biological changes a woman experiences during pregnancy (like pregnancy brain) and after childbirth do their part to help new moms with this most important of jobs.

Baby Brain—It’s Not What You Think

An international study that used MRI scans of the brain to compare men and women who’d recently had children with those who hadn’t revealed that new moms exhibited striking changes that persisted for two years after giving birth. The changes of pregnancy brain were so pronounced, experts could tell whether a woman had recently had a child simply by examining her brain scan. And these biological changes were limited to moms—the analysts did not observe similar changes in the men they tested.

“The changes look like a careful pruning of connections, perhaps in a way that helps a woman focus better on her baby,” Maggie Fox reported in Today. Contrary to the “baby brain” you often hear about—rumored to make moms scatterbrained and forgetful—the researchers discovered that women scored about the same in memory and vocabulary tests before and after giving birth.

The “pruned” areas of the brain seem to correspond with decoding other people’s thoughts and emotions, leaving new mothers with more attention to devote to creating healthy attachments with their children. “These results indicate that pregnancy changes the gray matter architecture of the human brain and provide preliminary support for an adaptive process serving the transition into motherhood,” the researchers explained.

‘Maternal Motivation’ Ensures Babies Are Cared For

We’ve already discussed the pruning effect researchers observed with pregnancy brain. But that’s only the beginning of how the brain evolves in response to becoming a mother. There’s an uptick in activity in the parts of the brain that govern empathy, anxiety, and social relationships.

“On the most basic level, these changes, prompted by a flood of hormones during pregnancy and in the postpartum period, help attract a new mother to her baby,” Adrienne Lafrance reports in The Atlantic. “In other words, those maternal feelings of overwhelming love, fierce protectiveness, and constant worry begin with reactions in the brain.”

Another biological change new moms face has to do with what researchers have termed “maternal motivation.” This is a mother’s almost obsessive concern for her child’s welfare. Maternal motivation shows up as heightened levels of activity in the amygdala, which continue to increase for months after the child is born.

“This growth, researchers believe, is correlated with how a new mother behaves,” according to The Atlantic. “An enhanced amygdala makes her hypersensitive to her baby’s needs—while a cocktail of hormones, which find more receptors in a larger amygdala, help create a positive feedback loop to motivate mothering behaviors.”

Keep in mind that these changes in brain activity can’t be explained away as simply a response to being around children in general. A Tokyo study revealed that women’s brain activity looks drastically different when they’re responding to their own child than when responding to a child who is not their own.

Breastfeeding Boasts Lasting Benefits—Not Just for Babies

Most of us are familiar with how valuable breastfeeding is to babies’ health. It turns out moms who breastfeed see some serious advantages themselves. Women who breastfed their children had fewer complications from diabetes, heart disease, and breast or ovarian cancer later in life. And the longer women breastfed, the lower their health risks were. (Women who were never pregnant saw similar risk levels as women who breastfed their children. Women who gave birth but did not breastfeed were the ones who saw increased risk levels.)

Scientists aren’t sure exactly why not breastfeeding seemed to open up these risks. According to Scientific American, “by not engaging in the process that the body prepares for during pregnancy, many crucial systems can go out of whack. And the effects can last for decades after children are weaned.”

The researchers suggest that the heart health benefits for breastfeeding moms may be linked to cholesterol. It’s normal for cholesterol numbers to go up when a woman is pregnant. But they observed that it took longer for new moms who weren’t breastfeeding to get their cholesterol level back down to what it was before they got pregnant—about 3 months longer.

Breastfeeding appeared to increase levels of high-density lipoprotein, or HDL, the “good cholesterol.” Blood pressure variation may also play a role. The scientists’ findings about cardiac health held true even when other potential factors, such as body mass index (BMI), family history, socioeconomic status, overall health, and lifestyle, were taken into account.

Finally, the chemical oxytocin, which women release while breastfeeding, promotes relaxation and a feeling of euphoria. In addition to working in the moment to help moms and babies bond, there are more lasting effects. Alison Stuebe, an assistant professor in the Division of Maternal Fetal Medicine at the University of North Carolina in Chapel Hill, explained, “Moms who breastfeed over long times get really good at releasing oxytocin.” That means they can count on this ingrained response to kick in and help them conquer stress long after breastfeeding is a thing of the past.

One thing is clear—few events in life have as much biological impact as motherhood. Our bodies go to work behind the scenes to help make parenting just a little easier and keep our children out of harm’s way. With all the increased brain activity and hormones, it’s no wonder Lafrance mused in The Atlantic, “becoming a parent looks—at least in the brain—a lot like falling in love.”


Fox, M. (2016, Dec. 19). Is ‘baby brain’ real? Yes, but not in the way you might think. Today.

Harmon, K. (2010, April 30). How breastfeeding benefits mothers’ health. Scientific American.

LaFrance, A. (2015, Jan. 8). What happens to a woman’s brain when she becomes a mother. The Atlantic.

Parker-Pope, T. (2008, March 7). Maternal instinct is wired into the brain. The New York Times.

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