Mummy brain: under the microscope
Picture: iStock
That was one in what was a long list of instances of ‘mummy brain’. For the first year after my baby was born, I found it difficult to concentrate on or remember anything that didn’t have to do with him.
Research now proves ‘mummy brain’ is a real phenomenon. It isn’t just women’s bodies that change in pregnancy and early motherhood. Their brains do too.
Memory loss is the most noticeable result of this change. Up to 80% of women report some form of memory loss during and after pregnancy, says Professor Jodi Pawluski, a neuroscientist who studies maternal behaviour at the University of Rennes in France and host of a podcast called ‘Mummy Brain Revisited’.
She noticed it herself when she was pregnant with her two children, now aged eight and nine. “I had classic verbal memory deficits where I couldn’t remember the simplest of words,” she says. “But because of my academic background, I knew about motherhood and the brain and was confident my biology knew what it was doing.”
Abigail Tucker, the author of and US-based mother of four, believed concentration gaps were due to mental overload. "I noticed changes when I became a mother but assumed it was just a cumulative lack of sleep and too many swimming lessons and dentists' appointments cluttering up my headspace," she says.
It was only when she visited labs where researchers studied the transition to motherhood by tracking the measurable neural changes that occur in new mothers as their brains change size and shape that she realised what was actually happening. "Mummy brain is very real," she says.
“Studies agree that there is some reduced cognitive functioning, especially in late pregnancy,” says Dr Richard Duffy, a consultant in perinatal psychiatry at the Rotunda Hospital, Dublin. “Some studies have demonstrated deficits in working memory, processing speed, and executive functioning.”
This research includes a 2018 review by academics at Deakin University, Australia. They reviewed 20 studies that had assessed more than 700 pregnant and 500 non-pregnant women and concluded that general cognitive functioning, memory, and executive functioning were significantly poorer in pregnant women.
The reason for this may lie in changes in the very structure of the brain. In 2002, a study carried out at the Imperial College of London found that certain areas of women's brains shrank during pregnancy.
In 2016, a team at Leiden University, Netherlands, published a study building on this research. They scanned the brains of 25 first-time mothers before pregnancy and again in the first few weeks after giving birth. They compared these scans to those of 20 women who had not given birth and found stark differences between the two.
The brains of women who had recently given birth showed such pronounced biological changes that a computer could distinguish them from the brains of the other women. Mothers' grey matter was reduced in certain areas.
The areas of the brain that lost volume included the hippocampus, which is associated with memory.
Other areas were affected too, with volume being lost in regions that control empathy, anxiety, and social interaction. However, researchers say this doesn’t necessarily have negative consequences.
"We don't want to put a message out there along the lines of 'pregnancy makes you lose your brain'," says lead author and neuroscientist Elseline Hoekzema. "Grey matter loss can represent a beneficial process, perhaps of maturation or specialisation."
"We often think a decrease is negative but that's not always the case," says Pawluski.
The Leiden study's authors say their findings may mean new mothers' brains are wired differently to allow them to respond better to their infants' needs. In support of this argument, they found that scores on a standard test that gauges a mother's attachment to her infant could be predicted to a significant degree based on the changes in her grey matter volume during pregnancy. The greater the volume loss, the stronger the attachment.
Two years later, 11 of the 25 mothers (those who had not become pregnant again) returned for further scans. They showed that the grey matter loss remained, except in the hippocampus, where most volume had been restored.
This corresponds with the professional and personal experience of Dr Liisa Galea, a neuroscientist and professor of psychology at the University of British Columbia, Canada. "When we test memory, changes during and after pregnancy are seen in the last trimester," she says. "They vary depending on whether or not it's your first pregnancy, getting a bit worse with subsequent ones."
She had an experience of this with her second pregnancy. "My children are now aged 23 and 25 and during the third trimester of my second pregnancy, I lost my car in the parking lot so often that it became embarrassing," she says.
Galea says that this doesn't last. As the subsequent recovery of volume in the hippocampus attests, it's likely to be a short-term problem.
Her own memory recovered fully. "I feel like I have a supercharged memory now," she says. "It's not perfect, but from work and family appointments to bringing pets to the vet, there are an amazing number of things I remember to do."
It may even be better than before. "Researchers such as Ann Marie de Lange, a neuroscientist at the University of Lausanne who specialises in women’s brain health, have shown that pregnancy is associated with less brain ageing," says Galea.
"We see a neurogenesis, or the birth of new brain cells, in the hippocampus of rodents. This is reduced in the middle of pregnancy but by middle age, it's higher in mothers than in non-mothers. So, early post-partum may involve some deficits but later on, there are potential enhancements."
The brain changes caused by pregnancy and motherhood don't just impact memory. In studies, mothers demonstrate a heightened capacity to stay calm and focused in stressful situations. For example, in a 2002 study at the University of Zurich when mothers were asked to stick their hands in buckets full of ice water for a minute, they had far less of the stress hormone cortisol in their blood than women who had never had children.
Motherhood may even make women smarter, according to a study co-authored by Galea in 2019. It found that female rodents got better at completing mazes after they weaned their pups.
What fuels these changes in our brains is up for debate. “Hormonal levels, sleep impairment, changes in brain grey matter volume, and the development of mental health conditions all play a role,” says Dr Duffy.
The hormone oxytocin may be particularly potent. It floods the bloodstream during labour, preparing women's bodies for birth. Scientists now think it may also trigger changes in women's brains.
In 2015, a study at New York University found that it changed the way auditory signals were processed in the brains of mice. Virgin mice who didn't respond to distress calls from pups became instantly responsive once they were given oxytocin, picking up the pups by the scruffs of their necks and returning them to the nest as their mothers would have done.
Sleep deprivation is another obvious factor that can affect a woman’s brain function. "New mothers lose an estimated 700 hours of sleep a year," says Tucker. "That takes its toll."
"Sleep deprivation plays a huge role in our cognitive abilities, regardless of whether we're parents or not," says Pawluski. "We should try to limit our cognitive and mental load to give our brains the chance to function as well as they can in late pregnancy and post-partum."
Tucker believes all women need to be told that 'mummy brain' is part of the process of pregnancy and early motherhood. "Just knowing our brains are changing is helpful," she says. "It's information we need so that we understand ourselves better.
Galea wants women to realise that rather than underperforming, their brains are working overtime to manage the steep learning curve associated with caring for a newborn baby. Instead of paying attention to relatively inconsequential information such as what day of the week it is, their brains are trying to read their baby's non-verbal cues to find out what it wants and needs.
However, Dr Duffy advises women to remain vigilant when it comes to their mental health. “While the experience of impaired memory is common in pregnancy, it is also a symptom associated with mental health conditions,” he says.
“With such high levels of depression and anxiety in the perinatal population (around 15%), it is important not to give pregnant individuals or new parents reason to dismiss what can be very important red flags that their mental health is suffering. So, if these symptoms occur with anxiety or low mood, do discuss them with a GP.”
Whatever mothers do, they certainly shouldn’t berate themselves the way I definitely did when I found my wallet chilling in my fridge.
Pawluski advises us to go easy on ourselves instead. "If we appreciated the amazing things that are happening to our brains during pregnancy and early motherhood, we might just give ourselves a break."
You’ve recently had a baby and are currently deep in the fug of early parenthood. You’re doing things like leaving the car keys in the fridge and forgetting what you need to buy as soon as you arrive at the shops. You have a definite case of ‘mummy brain’. But is there anything you can do about it?
Tracy Donegan, a midwife and founder of www.gentlebirth.ie, has some advice.
1: Accept that what you’re experiencing is a normal outcome of pregnancy and motherhood and not a permanent form of cognitive decline. “Your brain undergoes an important restructuring so that you will bond with and therefore protect your baby,” says Donegan.
2: Get organised so that you don’t forget to attend to important tasks. “When I had my children, now 18 and 11, I felt a dense fog descend on me during those first few months of motherhood,” says Donegan. “Post-its and notes in my phone became my best friends!”
3: Take full advantage of all the support that is available to you. You are bound to be short of sleep at this stage and any opportunity for rest should be grabbed with both hands, especially as sleep deprivation is known to have a detrimental effect on cognitive function.
4: Eat well. There’s a lot happening in your body and in your brain. They need all the nutrients they can get.
5: Reduce your mental load if possible. Being forgetting and having trouble concentrating could be your brain’s way of telling you that too much is going on and it’s time for you to slow down.
6: Remember that these changes are likely to be noticeable only to yourself and to those close to you. ‘Mummy brain’ does exist but it shouldn’t interfere with daily functioning. If it becomes a concern or if you have a real issue with being unable co concentrate, talk to your GP.
7: “Above all,” says Donegan. “Be gentle with yourself and your baby.”
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