Most women will admit their brains turn to mush during pregnancy. From missing doctor’s appointments to not remembering their own phone number, bouts of forgetfulness are all part of pregnancy-induced mental fog. It turns out this is likely the result of sleep deprivation and exhaustion.

So, what exactly happens inside a mother’s brain?

In Discovery News’ video, “Can Giving Birth Permanently Change Your Brain?,” host Lissette Padilla explains how mothers experience neurological changes at the start of pregnancy that continue throughout the postpartum period. In a study published in the journal Behavioral Neuroscience, researchers observed moms' brains at two to four weeks after giving birth, and then again around three months later, using MRI technology. They found an increase in gray matter in certain brain regions, including the parietal lobes (back of the brain), prefrontal cortex (front of the brain), among many others.

Furthermore, some of the growth happened in areas like the amygdala and the hypothalamus which are associated with emotional regulation, survival instincts, and hormone products. These changes seem to be linked to a mother having a positive view of her baby and an increase in positive feelings towards them. This is what helps moms get up five to six times a night for a screaming baby, without getting extremely frustrated.

Researchers at the University of Toronto in Mississauga wondered if there were notable differences in the amygdala when mothers looked at their babies versus the babies of strangers. In the study, the researchers analyzed the brain activity of 22 mothers and found some mothers would respond more strongly to their own babies, reporting higher feelings of satisfaction with motherhood, a more positive mood, and generally good experiences with being a mother.

Meanwhile, when the amygdala did not become more sensitive during motherhood, it affected the bond between the mother and child negatively. Women who showed reduced amygdala responses to the photos of their babies were more likely to have poorer quality of maternal experience, including increased levels of stress and anxiety. They also had a hard time with motherhood.

In fact, postpartum depression is associated with the binding sensitivity of receptors in the brain that affect the amygdala and other structures involved in the dopamine reward system. Interestingly, the same neurological processes that are involved in falling in love romantically are also involved in a mother loving her baby. Oxytocin, the “love hormone,” plays a role in bonding and affection in relationships. Overall, much of what happens in a new mother's amygdala has to do with the hormones flowing to it.

The hormone is released when women are giving birth, and it's also associated with breastfeeding, which helps facilitate bonding with a newborn. Oxytocin spikes during pregnancy, and regions with a high density of receptors for oxytocin, like the amygdala, are specifically activated in mothers' brains when responding to babies’ faces and scents.

So, in reality, simply caring for one's baby leads to a boost in brain activity and a growing brain.