Did you know that giving birth causes your brain to actually grow larger? Research has shown that changes occur in a woman’s brain during childbirth and continue during motherhood.
That’s important because the area of the brain that is growing helps in developing the skills it takes to be a good mother.
Through these studies, scientists hope to better understand what motivates mothers to care for their babies. While many women seem to instantly develop the instinct to protect and nurture their child, some women lack what is traditionally thought of as a “normal response” to their child.
"With this research, we hope to better understand how to support moms who don't naturally experience a brain reward response when they interact with their baby," said Dr. Lane Strathearn, a developmental pediatrician at Baylor College of Medicine in Houston, Texas.
In the future, this field of study could lead to treatments that help women with mental illness or who lack certain types of normal brain responses. "We're currently researching whether giving moms oxytocin, a hormone that triggers a reward response in the brain, could influence their response to their child," Strathearn said.
In a 2010 study, researchers examined the brain scans of 19 women before they gave birth and after they gave birth. They discovered that the size of the mothers’ brains increased shortly after childbirth.
"We observed small but significant increases in the volume of gray matter in the brain," said study co-author Pilyoung Kim, a developmental psychologist who performed the research at Yale University.
Kim and colleagues also found that moms who gushed over their babies a month after childbirth showed the greatest growth in parts of the brain, compared with moms who didn't respond as enthusiastically.
After childbirth, moms begin to develop important mothering skills that help them tune into the needs of their baby. Research suggests that changes to the brain may be linked to how well these skills develop.
The areas of the brain where scientists see the most change are the:
- Hypothalamus (Produces hormones that control body temperature, hunger, moods, sleep, thirst, sex drive and releases hormones to the pituitary gland.)
- Amygdala (Plays a key role in the processing of emotions.)
- Parietal lobe (Plays important roles in integrating sensory information from various parts of the body, knowledge of numbers and their relations, and in the manipulation of objects.)
- Prefrontal cortex (Responsible for regulating behavior. This includes mediating conflicting thoughts, making choices between right and wrong, and predicting the probable outcomes of actions or events.)
You can see how each of these areas plays an important role in developing good mothering and parenting skills.
Kim’s team found that the more enthusiastic mothers were more likely to develop bigger mid-brains than the less enthusiastic moms. The growth in this particular area of the brain is linked to maternal motivation and rewards as well as regulation of emotions.
The researchers said this expansion in the brain's "motivation" area might lead to more nurturing, which in turn could help babies thrive. Still, "we don't know whether it's the experience that changes the brain, or the brain that changes the experience," said Kim, who is now with the National Institute of Mental Health.
So, what causes the brain to actually grow? Researchers are not quite sure but say it might be an increase in the hormones estrogen, oxytocin and prolactin.
Another key to the puzzle might be the brain’s production of dopamine, a chemical messenger that sends the signal that “this feels really good.” Once the brain receives these signals it looks for ways to repeat the experience. More maternal behavior spurs more pleasure and hence more dopamine.
In Strathearn's 2008 study published in the journal Pediatrics, when mothers saw their babies’ smiling faces, their reward signals became activated.
"These are similar brain regions that are activated when a cocaine addict gets a shot of cocaine," said Strathearn said. "So for moms, it may be like having a natural high."
Motherhood may not only influence the mom’s brain but also her child’s.
In a 2009 study published in the journal Neuropsychopharmacology, researchers looked at two groups of mothers, dividing them based on how attached they felt to their own mothers.
They found both groups responded differently to their infant's faces.
"For mothers with 'secure' attachment, we found that both happy and sad infant faces produced a reward signal in their brain," Strathearn said.
But moms with an "insecure" attachment didn't show the same brain response. When they saw their baby cry, part of the brain that is linked with pain, unfairness or disgust became activated.
"Biologically, there seems to be a pattern that is repeated from one generation to the next," Strathearn said. "Early experiences we have in childhood play an important role in the pattern of brain development."
Strathearn said that in early infancy, "the brain is being sculpted in response to its social environment, like being rocked and touched." But he noted that many factors, including genetics and the environment, also influence a child's development.
More brain growth and certain chemical reactions seem to be nature’s way of helping mother’s become good at mothering.
So there you have it, motherhood makes a woman’s brain larger. That’s a good thing - because we all know that you’re going to need every brain cell you can get to help you master parenthood.