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What is Pregnancy Brain and When Does it Occur?

What is Pregnancy Brain?
'Pregnancy brain' is characterized by short-term memory loss or forgetfulness, which some women experience during those nine months. But, can pregnancy really affect memory and the cognitive abilities of a woman? Find out here whether pregnancy brain really exists or it is just a myth.
Chandramita Bora
Last Updated: Dec 21, 2017
Did You Know?
During pregnancy, a woman's brain can shrink by up to 8%, though she does not lose her brain cells.
Pregnancy is a stage of transition, and a woman has to go through a lot of physical and emotional upheavals during this period. Mental sluggishness and loss of memory, or forgetfulness, is one such common problem during pregnancy, which is termed by many as 'pregnancy brain', 'pregnesia' or 'placenta brain'. While experts are skeptical about the existence of 'pregnancy brain', a great majority of women claim that they actually experienced this condition during those nine months.

No wonder the failure to remember even the simplest everyday tasks can be quite frustrating for a pregnant woman, when she is already battling a host of other issues (morning sickness, constipation, mood fluctuations), caused by surging hormone levels. So, what exactly is 'pregnancy brain'? Is it a myth or an inevitable part of pregnancy? Let's find out more about what people like to call 'pregnancy brain'.
What is Pregnancy Brain and When does It Occur?
As mentioned already, pregnancy brain is a condition - supposedly induced by pregnancy - where a woman experiences 'brain fog' or trouble in concentrating and remembering things. Women usually complain about this condition during their first and third trimesters. Many women on the other hand, experience it after childbirth, which is termed as 'mommy brain'.

However, studies conducted to examine the relation between pregnancy and memory are very limited, and most of these studies have produced conflicting results. While some studies have found that pregnancy may have an effect on memory and cognitive abilities, others maintain that the results of cognitive tests conducted in expectant mothers and women who are not pregnant are almost similar.

So, there is not enough evidence to back the claim that 'pregnancy brain' or 'pregnesia' is a real condition. Nevertheless, it cannot be completely denied that the physical, mental, and emotional changes associated with pregnancy may have an impact on the memory of a woman. So, what exactly does happen during pregnancy? Does the brain shrink during pregnancy and cause memory loss? Or is mommy brain just an illusion? Let's find out some of the possible explanations about the pregnancy-induced 'brain fog' that many women experience.
What are the Possible Causes
Surging Hormones
Pregnant Woman suffering from headache
The sex hormones, estrogen and progesterone, fluctuate greatly during pregnancy, which can cause mood swings, fatigue, increased sleepiness, and headaches. Moreover, the hormonal surge in the first few weeks can alter the way in which the brain processes sensory information, especially those coming from the olfactory glands. This is the reason a woman becomes extremely sensitive to certain odors during pregnancy.
So, it is presumed that if these hormones can change a woman's perception about taste and smell, they may have an effect on her memory as well.
Increased Level of Stress and Anxiety
Worried Pregnant Woman
It is quite natural for expectant mothers to be preoccupied with thoughts of the baby and the new challenges that motherhood will bring into their lives. However, sometimes this preoccupation can leave little room for other issues, and cause distraction. In other words, a pregnant woman can sometimes become so anxious and worried about the health and safety of her unborn baby that she may end up being forgetful.
The nesting phase, where a woman feels an irresistible urge to prepare a home for the newborn, may also be associated with 'pregnesia'. Because of her nesting instinct, a pregnant woman can become so obsessed with cleaning and preparing the house for the new member, that she may forget about other day-to-day activities.
Sleep Deprivation
Sleeping Pregnant Woman
Sleep deprivation is perhaps one of the most common complaints that women complain of during pregnancy and the first few months of motherhood. Both men and women need 7 to 8 hours of good sleep to feel mentally and physically alert. So, lack of enough sleep can take a toll and cause mental sluggishness, which can be interpreted by expectant and new mothers as 'pregnancy or mommy brain'.
Changes in the Brain
In 1996, a report published in the New Scientist Magazine found that the brain of pregnant women shrunk during their third trimester. Another study published in the American Journal of Neuroradiology in 2002, also revealed that the volume of the brain reduced by about 4% during pregnancy. However, the brain usually regains its original size within a few weeks after childbirth. But in some cases, the brain can take up to six months to attain its former size.
Scientists are not sure why the size of the brain changes during pregnancy, but it is assumed that changes in cellular metabolism, required for reconstructing the brain circuits, may be responsible for it. However, a woman does not lose brain cells during pregnancy, and hence, the shrinkage is certainly not caused by the loss of brain cells. Further, experts are not sure whether the pregnancy-related brain shrinkage is in any way related to memory. But, it is suspected that the process of restructuring the connections between the brain cells may have a relation with 'pregnancy brain'. Yet another theory suggests that 'pregnancy or mommy brain' can be an evolutionary development which helps a woman focus more on her baby by making her unmindful of outside distractions.
A Belief in the Existence of Pregnancy Brain
Many experts brush off the existence of pregnancy or placenta brain, and consider it mostly as a psychological phenomenon. They are of the opinion that many women tend to be more aware of the minor lapses in their memory and cognitive abilities during pregnancy, because of their firm belief in the concept of 'pregnesia'.
Group of pregnant women
In fact, one study found that a group of pregnant women thought that their performance was worse than what it would have been before pregnancy, even though they actually did as good as the women who were not pregnant.
Can Pregnancy have a Positive Effect on the Brain?
✤ It has been observed that from the moment of conception, the brain of a pregnant woman undergoes many changes. New circuits are developed in the brain to prepare a woman for motherhood. Moreover, it has been observed that while some areas of the brain can shrink in size during pregnancy, other areas, especially the forebrain, can expand. The forebrain is responsible for reasoning and problem-solving, and so, its expansion may sharpen these skills.
✤ Some animal studies have observed that mothers have a better memory and they are more courageous than females without children. They are also better hunters and providers, as compared to the females who have not given birth.
✤ Professor Helen Christensen, director of the Center for Mental Health Research at the Australian National University, is of the opinion that pregnancy can have a positive effect on the functioning of the brain. So, with pregnancy, a woman can expect to have better mental abilities than before. After all, a mother needs to be more vigilant and alert to protect her child. Similarly, childbirth and breastfeeding may also have a positive impact on brain function.
But if pregnancy changes the brain for the better, then why does a woman experience 'brain fog' during this period? Experts are of the opinion that sleep deprivation can mask the improved mental abilities of a pregnant woman. For many women, memory loss during pregnancy can become very troublesome. However, a woman can overcome it to a great extent by writing down all her important tasks, reducing her workload, following a balanced diet, getting enough sleep, and exercising regularly.