The Cognitive Science Behind “Pregnancy Brain”

Most people who have experienced pregnancy can likely attest that “pregnancy brain” is a real phenomenon. Pregnancy brain or “momnesia” are colloquial names for brain fog and forgetfulness experienced while pregnant. What does cognitive science have to say about pregnancy brain?

pregnancy and cognition

How does pregnancy brain work?

Pregnancy brain is proven to be a real thing by cognitive science! During pregnancy, the body experiences physiological changes including significant hormone fluctuations. These can impact cognitive function, including temporary impairments to memory and executive function.

Environmental factors also play a big role in cognitive function during pregnancy. Pregnancy is a life-changing experience, which can easily cause difficult emotions such as stress and worry. These emotions can affect memory. It can also lead to trouble sleeping, which comes along with cognitive effects such as difficulty with executive functioning. Additionally, expecting parents frequently become hyperfocused on preparing for the baby’s arrival. It’s no surprise that our brains may be distracted from other functions due to this concentration in one area.

Put all of these factors together, and it would be shocking if you didn’t experience some level of brain fog, absentmindedness, or forgetfulness while pregnant! If you or a loved one are experiencing pregnancy brain – don’t worry. It might be frustrating, but it’s completely normal and it doesn’t last forever.

How long does it last?

Once the baby is born, pregnancy brain should begin to subside – however there are other factors affecting the parents’ cognition. Parents aren’t likely to sleep well for the first several months as newborn babies need care multiple times throughout the night. So, it’s hard to determine where “pregnancy brain” ends and “sleep deprivation brain” begins.

However, once the baby is old enough to sleep through most of the night, parents will be able to get more sleep as a result. At that point, forgetfulness and brain fog will likely lessen. If you find that you’re still experiencing trouble with cognitive function many months after pregnancy, it may be beneficial to speak with your doctor. You deserve to feel happy and cognitively healthy!

Your body isn’t the only thing that changes

Other changes occur in the brain during pregnancy. However, these changes generally indicate positive developments and don’t interfere with day-to-day life. Studies have found that the grey matter of the brain decreases during pregnancy. Before you think “That sounds scary!” let us assure you that less volume does not necessarily equate to less function. In this case, it actually just indicates a honing of new skills and a shift in priorities, which is to be expected! When you are preparing to bring a child into the world, your priorities shift to the task of caring for that child, which means that your brain is developing a more specialized function. There is debate as to whether these changes are lifelong or only last a few years. More research is needed to determine the answer.

A similar decrease in grey matter occurs during puberty, indicating maturation and a focus on new functions. Throughout our lives, the brain can restructure itself in response to change. It simply shows that we’re growing and adapting to life changes.


Pregnancy brain is real. While it can be frustrating or even concerning to notice changes in your cognition, it generally goes away after pregnancy. As always, there are many factors in life that can affect cognition, such as the stress of having a new baby. So, whenever possible, self-care measures may help to keep cognition healthy. Getting rest, exercising, eating healthy, lowering stress, and socializing are a few ways to care for cognitive health during pregnancy and beyond.

Aly Castle

Aly is HappyNeuron Pro’s Content Specialist. She is passionate about mental health and well-being and loves utilizing her design background to share important cognitive information clearly and understandably.

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