The Unexpected Neuroscience of Mommy Brain

Mommy Brain

While most mothers-to-be are aware of the hallmark symptoms of pregnancy—nausea, fatigue, tender/swollen breasts, sensitivity to smells, loosening joints, swelling hands and feet, hair and skin changes, etc.—the profound changes to the brain during the same period are often overlooked or grossly misunderstood. “Mommy brain” is the term given to the symptoms of mental fogginess and forgetfulness without a deeper grasp of the brain metamorphosis taking place.



Based on research developments in recent years, experts now believe that a woman’s brain essentially restructures itself to be better prepared for the demands of being a mother. Click To Tweet

In recent years, researchers have come to understand that pregnancy and early motherhood is a period of radical change to the female brain. In fact, the brain undergoes its most rapid and dramatic changes during this time than at any other time in a mother’s life, including puberty.

Mommy brain symptoms are likely an indication of something greater happening in the brain—a transformation of sorts. Based on research developments in recent years, experts now believe that a woman’s brain essentially restructures itself to be better prepared for the demands of being a mother. The altered brain appears to help women be sensitive and effective caretakers who are less affected by stress and more focused on the needs of their infants. What’s more, the brain changes during pregnancy and early motherhood may likely boost brain function permanently.

It seems “supermom brain” would be a more fitting term for this period of transformation! Let’s take a closer look.


Mommy brain generally refers to the cognitive changes, such as momentary memory lapses and brain fogginess, that happen anytime during pregnancy or after birth. It’s also called pregnancy brain, mom brain, momnesia, or baby brain, and it is very common. Between 50 and 80% of pregnant women report thinking problems during pregnancy and postpartum, according to the American Psychological Association.

Mommy brain is a real occurrence. A recent 2021 study measured the cognitive function of pregnant women in their second and third trimesters. The study found “an impairment in memory among pregnant women” and noted that language skills, particularly naming, were also diminished.

While mommy brain can partly result from lack of sleep and multitasking, researchers believe it has more to do with a surge of pregnancy hormones. There are 15 to 40 times more progesterone and estrogen “marinating” the brain during pregnancy. Progesterone is known to have a sedating effect, which could affect cognition. The hormonal influx likely triggers the architectural changes within the brain, which factors in as well.


Starting in the early 2000s, scientists began taking note of structural changes in the brain related to pregnancy. A 2002 study found that women’s brain volume diminished by about 4% during pregnancy, then returned to normal after delivery.

Interestingly, this apparent brain shrinkage is not the deficit that it might appear to be. It does not seem to be the result of brain cell loss but rather changes in cellular metabolism. Dr. Louann Brizendine, in her book The Female Brain states that the shrinkage is a sign of brain circuits that are being restructured in preparation for their being changed from “one-lane highways” into “superhighways.” Think of it as restructuring for greater efficiency.

A number of animal studies examining the effects of pregnancy on the female mammalian brain followed with remarkable results. Research published in Scientific American showed mother rats to be better, more efficient learners who are less fearful and are therefore better providers for their young compared to non-mother females. Mother animal subjects were also more resistant to stress and showed enhanced memory and cognition.

The researchers theorized that the pregnancy brain undergoes revolutionary changes, at first appearing to be a disorganized construction zone, which may account for mommy brain symptoms. However, once the infant is born and the neuronal changes start to organize and take hold, the result is a better brain. The transformed mother brain is more efficient and focused, having evolved from a self-centered organism to an other-focused caregiver.

What’s more, a 2011 animal study conducted by the same lead researcher suggests that better cognitive skills and protection against neurodegenerative disease may last well into later life.


Impressed with the research findings on pregnancy and enhanced brain function in animals, scientists set out to learn more about the transformative brain changes in human subjects. A 2017 breakthrough human study found that new mothers experienced gray matter reductions that lasted for at least two years after birth – and this apparent loss came with important benefits.

The gray matter shrunk around the brain regions involved in social cognition, and mostly in the network dedicated to the theory of mind. This is the region that helps us think about what is going on in someone else’s mind. When the new mothers looked at photos of their infants, it was these areas that had the strongest response. Researchers observed that where there was the greatest mother-infant bonding, there was also the greatest consolidation of gray matter.

Scientists call the phenomenon of gray matter shrinkage “gray matter pruning.” A similar process happens in early childhood and adolescence. The gray matter has myriad interconnections among neurons, and during pruning, the most important connections are strengthened while the others are left to perish. Rather than indicating a loss of function, pruning means that a brain region has become more specialized. This specialization is what will help new mothers adapt to motherhood and respond to the needs of their baby.


The research on brain plasticity during pregnancy and early motherhood is ongoing. In a newer study published in the Archives of Women’s Mental Health, brain plasticity is recognized in areas that implicate caregiving, namely regions involved in reward/motivation, salience/threat detection, emotional regulation, and social cognition (such as the ability to understand and respond to the mental state of the baby).  Yet, this new study explores how these changes also make certain women vulnerable to the development of mental disorders such as postpartum depression. While the research is not conclusive at this point, it hopefully can lead to the prevention of these disorders, which can threaten both the mother and child.


If you or someone in your life becomes pregnant, remind yourself or that person that the forgetful, foggy brain of pregnancy is actually a sign of a stronger, more able supermom brain in the making.

Perinatal mental health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, clinical evaluations, and therapy for adults, teens, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.


  1. Is there any supplements we can take during this transition? (Pregnancy and postpartum)

    Comment by Ireris Petras — March 19, 2023 @ 7:50 AM

  2. Hello Ireris, thank you for reaching out. For more information about Dr. Daniel Amen's recommended, brain-directed supplements, visit

    Comment by Amen Clinics — March 21, 2023 @ 9:43 AM

  3. Hello,
    Thank you for this detailed article it’s really helpful. I gave birth 18 month ago and I am breastfeeding since then. I still have the feeling my brain is not the same as before the pregnancy especially regarding memory. It is really affecting me as I feel that I am not as good as before at my work which involves a lot of planning and organisation. Is it possible my brain will fully recover after giving up breastfeeding?
    Thank you so much and best regards from Germany

    Comment by Sophie — November 6, 2023 @ 12:49 PM

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