Does pregnancy alter moms’ brains?

 

Everyone knows pregnancy has a lot of effects on a woman, from mood swings to the obvious change in abdomen diameter. However, many wonder if some changes are less obvious and much more long-term—if the brain of mothers themselves are altered permanently by pregnancy.

The notion would certainly make sense. During pregnancy, women experience hormonal fluctuations more massive than any other time in their lives—even above brain-altering puberty. According to a 2011 review, there are some indications that these brain changes occur, but the evidence is less than desirable. “Pregnancy is a critical period for central nervous system development in mothers,” said author and psychologist Laura M. Glynn in a press release. “Yet we know virtually nothing about it.”

Momnesia is a real thing

In the short term, these hormones trigger mood swings, cravings, and, according to a 2010 study, probably “momnesia”—the memory problems pregnant women often face as the pregnancy progresses. The 2011 review further backs up these claims, suggesting “Mommy Brain” may be symptomatic of physical changes in the brain brought on by these hormones. The hormones probably help a woman shift into the role of a mother, decreasing stress and attuning her to her baby’s needs, but forgetfulness is the cost.

One hormone in particular is known to spike: Oxytocin. “We see changes at both the hormonal and brain levels. Maternal oxytocin levels—the system responsible for maternal-infant bonding across all mammalian species—dramatically increase during pregnancy,” brain researcher Ruth Feldman told The Atlantic. (Oxytocin, made especially famous by studies in prairie voles, also increases in dads, too.)

It is often hard to study the brains of humans directly, so much of what we know about pregnancy brains comes from mouse and rat studies. Studies have found that pregnancy drives rats’ brains to form new neurons for the purpose of smelling—a change that lasts. Moreover, it’s known that fetal cells enter the mother’s blood in humans, but in mice, they tend to collect in the brain (especially the smelling parts) and stay there. This seems to aid in offspring recognition.

The same seems to hold true in humans—although we don’t know for certain. However, it has been shown that new mothers’ pleasure centers light up when they smell their baby, probably helping them to bond.

In other words, it seems that pregnancy may permanently change moms’ brains in order to transform them into more effective (and affective) parents—probably leading to the disorganized thoughts and forgetfulness as the hormones flood the brain and force it to change. So any partner complaining about running out for 3 AM waffle fries or tuna fish may want to tone it down a notch!

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Feature image: Thinkstock