What Happens to the Brain During Pregnancy

Why Pregnancy Brain Is More Than Just a Myth

Pregnant woman holding stomach
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Pregnancy marks a period of remarkable change in woman's body. In addition to the obvious physical changes, women frequently report that bringing a new life into the world also seems to have a major impact on the brain. While pregnancy brain—or the feeling of forgetfulness, inattention, and mental fogginess that sometimes accompanies pregnancy—is a common complaint, not all studies support the idea that women experience declines in cognitive abilities during pregnancy.

Some recent research suggests that pregnancy does have an impact on the brain. Is pregnancy brain real? And are there any long-lasting effects of pregnancy on the brain?

What Exactly Is "Pregnancy Brain?"

At some point during pregnancy, a woman may find herself feeling like her little bundle of joy has hijacked not only her body but also her mind. Lost keys, forgotten appointments, and misplaced wallets are just a few symptoms of this common mental fog.

While there is a great deal of research on the interaction between women's physical health and prenatal development, only fairly recently have researchers began to look into the ways that having a child affects women's health. Pregnancy is a period marked by massive changes in the body, including dramatic hormonal shifts, and in recent years psychologists have become increasingly interested in learning more about how pregnancy affects mothers, both physically and mentally.

Some researchers believe that these brain changes help make expectant mothers better prepared for the rigors of caring for a newborn, such as improving her abilities to cope with stress while also making her more attuned to her infant's needs. While "pregnancy brain" might lead to bouts of feeling forgetful, the upside is that these shifts can lead to more sensitive and responsive mothers.

However, not all studies point to any major cognitive differences between pregnant and non-pregnant women. For example, a 2014 study looked at pregnant women in ​their third trimester, women who were three months postpartum, and non-pregnant controls. While both pregnant and postpartum women reported higher self-rated levels of memory problems, the results of the study found no differences between controls and pregnant/postpartum women on a range of measures related to memory, attention, and executive functioning.

Changes in the Brain During Pregnancy

While not all studies agree, most evidence suggests that women do experience measurable declines in a variety of cognitive skills during pregnancy.

Impacts on Memory

For example, one 2007 meta-analysis looked at 14 different studies comparing pregnant and postpartum women to healthy, non-pregnant controls on measures of memory. What the researchers discovered was that pregnant women experienced significant impairments on certain measures of memory, but not all.

More specifically, they found that tasks that place a high demand on executive cognitive control may be significantly disrupted during both pregnancy and the postpartum period. Areas that were particularly impacted by pregnancy included free recall and working memory.

Free recall is the ability to remember items from a list while working memory is a type of short-term memory that involves immediate conscious experiences. This explains, perhaps, why pregnant women sometimes report struggling to recall details such as names and dates, as well as that general "foggy" feeling that expecting mothers often experience.

The researchers suggested that while well-rehearsed memory tasks, such as remembering the names and phone numbers of close family members, were unlikely to be affected, novel and challenging memory tasks were more susceptible. Having to recall five to six digits for a short amount of time, such as a new phone number, could become more difficult for expecting women.

Improvements in Recognition

A 2009 study found that pregnancy was associated with some declines in free recall, but that recognition memory did not become worse as a result of pregnancy. In fact, the study showed that, if anything, recognition memory was actually slightly better during pregnancy than during the postpartum period.

Changes in Gray Matter

So while pregnancy is linked to changes in both subjective and objective cognitive abilities, does pregnancy actually lead to changes in the brain itself?

One study found that pregnancy does indeed cause striking changes in women's brains, so much so that researchers are able to tell if a woman has had a child simply by looking at her brain scans.

What exactly do these changes entail? One study found that gray matter actually shrinks in areas of the brain associated with processing and responding to social signals.

The study's lead author, Elseline Hoekzema, noted that this certainly does not mean that 'pregnancy makes you lose your brain.' Instead, she suggests, the loss of brain volume in these areas may indicate a process of maturation and specialization, allowing women to become more focused and attuned to the needs of their infants.

What Causes Pregnancy Brain?

So while it is clear that most studies support the idea that there are at least some significant changes going on in women's brains during pregnancy, the causes of these neurological changes are not completely clear. Some of the factors that may be implicated include the following.

Hormones

As with many other symptoms associated with pregnancy, hormones are often blamed for these memory problems. Some researchers have suggested that elevated levels of sex hormones present during these stages of pregnancy could affect areas of the brain that play a role in certain memory tasks.

One study found that pregnant women scored lower on spatial memory tasks than non-pregnant women and that these memory disruptions tended to grow worse as pregnancy progressed. Researchers also measured levels of different sex hormones and had participants complete a questionnaire to assess mood and anxiety levels.

The results indicated that women in their second and third trimesters of pregnancy performed significantly worse on the memory tasks and also experienced lower moods and more anxiety. Interestingly, the study found no association between hormone levels and memory test scores.

Sleep Deprivation

Physical changes during pregnancy may play a role in pregnancy brain, but lifestyle factors certainly have an influence as well. Sleep, or the lack thereof, may also be a potential culprit. Sleep deprivation, which can become more pronounced as sleep becomes increasingly uncomfortable as pregnancy progress, can also play a major role. Sleep-deprivation often becomes more of a problem postpartum as well, as many new mothers find themselves losing out on significant amounts of sleep as they care for their newborns and adjust to the new demands of motherhood.

Stress

Increased stress levels associated with becoming a parent might also play a partial role in contributing to pregnancy brain. As mentioned previously, at least one study has found anxiety levels tend to increase as pregnancy progresses, and stress levels may raise further post-birth. The first few months of caring for a newborn can be particularly demanding and lead to elevated stress levels.

The exact causes of pregnancy brain are likely multifaceted. A combination of hormonal changes, increased stress levels, and sleep disturbances might all contribute to difficulties with memory and attention that pregnant and postpartum women report experiencing. After all, becoming a parent places all kinds of demands on women, both physically and mentally, so there is bound to be some type impact on the mind as well as the body.

Implications

So what do all these changes in the brain really mean? Are there any long-term effects on a woman's health?

Evidence suggests that many of the changes that take place in the brain during and after pregnancy have a beneficial effect on a woman's ability to care for her children. One 2010 study found that women undergo changes in areas of the brain, including the hypothalamus and amygdala, that are critical for emotional regulation.

Neuroscientists found that changes in estrogen, prolactin, and oxytocin hormone levels after birth may help reshape women's brains in response to their infant's needs. The findings suggest that new mothers actually experience a build-up in key areas of the mid-brain linked to motivation and behavior, perhaps playing an important part in the drive to care for an infant.

The researchers used MRI scans to look at the brains of women who had just given birth. Comparison images taken at two and four weeks postpartum revealed a small but significant increase in gray matter volume in specific areas of the brain. The areas where this volume increase were seen include the hypothalamus (which is associated with maternal motivation), the prefrontal cortex (which is associated with judgment and reasoning), and the amygdala (which is associated with emotional processing).

Perhaps more surprising, mothers who reported feeling more awestruck and "in love" with their infants were much more likely to also display this mid-brain enlargement. The amount of gray matter volume changes also corresponded to how attached mothers were to their infants. Mothers who reported stronger feelings of attachment displayed greater changes in gray matter volume. The study also found that when new mothers were shown pictures of their infants, they experienced increased activity in social areas of the brain.

A Word From Verywell

Changes in the brain during pregnancy may lead to some memory and attention difficulties, but these changes also appear to have important benefits. While more research is needed, it is clear that pregnancy is a critical time of neurodevelopment. Pregnancy leaves a mark on both the body and the brain, and emerging research suggests that some of these changes are enduring.

Alterations in the brain may indicate that specific areas become increasingly specialized in response to pregnancy. So if you find yourself feeling forgetful and inattentive during pregnancy, don't worry, you're not losing your mind. You're just building a brain that is more responsive to the many demands of parenting.

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