How Pregnancy Changes Your Brain: The Science Behind Baby Brain

Dr Natalie Hutchins
May 19
7 min read

By Eleanor Riches and Dr Natalie Hutchins

Your brain changes during pregnancy — What happens to your brain during pregnancy?

Most of us have heard of “baby brain”. That foggy feeling, the forgotten keys, the mental blanks mid-conversation; all chalked up to pregnancy. It’s become one of the most widely accepted, often joked-about symptoms of expecting a baby.

But what if “baby brain” isn’t just a harmless myth or a hormonal side-effect? What if it’s a sign of something deeper (and more powerful) happening under the surface?

In the past decade, scientific interest in the maternal brain has exploded. New imaging technologies and long-term studies have finally started to catch up with something women have known instinctively: pregnancy doesn’t just change your body, it changes your brain. Not in a way that signals damage or decline, but in a way that’s purposeful, adaptive, and pretty inspiring.

Let’s walk through what the science actually says and what it means for the way we experience, talk about, and support the maternal mind.

What Happens to Your Brain During Pregnancy?

Matresence (pregnancy and the transition into motherhood) is a major life event that reshapes the brain. These changes trigger increased neuroplasticity – the brain’s ability to change and adapt.1 In short, pregnancy doesn’t damage your brain; it reorganises it.

In 2017, a groundbreaking study scanned the brains of women before and after their first pregnancy. What they found was striking: pregnancy leads to specific, measurable reductions in grey matter volume.2

Grey matter is the part of the brain responsible for processing information, decision-making, memory and social understanding.3 In other words, the mental and emotional heavy lifting of daily life. The grey matter changes in this study were so clear that researchers could predict, with almost perfect accuracy, whether a woman had been pregnant just by looking at her brain scans.

To be clear, “grey matter reduction” doesn’t mean brain damage. It’s part of a process called synaptic pruning, the brain’s way of fine-tuning itself by trimming away unnecessary neural connections. Think of it like pruning a plant, cutting back what’s no longer needed so newer, stronger growth can thrive. It’s the

same kind of streamlining that happens during adolescence, helping the brain become more efficient.

So, it's not about losing function; it's about specialising. In this case, the brain is strengthening pathways that support caregiving, emotional responsiveness, and attunement to others (all crucial for bonding with a newborn).

Follow-up research six years later showed these changes were still present, reinforcing the idea that pregnancy can lead to long-lasting shifts in brain architecture.4

U-Shaped Curve: The Brain Shrinks and Rebuilds in Pregnancy

A 2025 study took things a step further by tracking women from before conception to six months postpartum.5 It’s one of the most detailed timelines we have of a brain’s perinatal transformation.

Here’s what they found:

Grey matter volume declines during pregnancy, reaching its lowest point just before birth.
After birth, brain volume starts to recover. But it doesn’t return to pre-pregnancy levels by six months postpartum.
Changes closely mirrored levels of oestrogen, a key hormone that surges during pregnancy and plummets after birth.

This U-shaped pattern tells us that the brain isn’t just reacting to pregnancy, it’s adapting to hormonal cues in a highly coordinated way.

The way grey matter recovers after childbirth also seems to influence how women develop maternal behaviours. Women who showed better grey matter recovery reported stronger emotional bonds with their babies and less frustration or hostility, suggesting these changes are a purposeful part of preparing for motherhood.

The study also found that women with better mental health had stronger grey matter recovery, highlighting how emotional well-being can influence brain adaptation, and reinforcing the importance of support and community after giving birth.

How Does the Brain Adapt Postpartum?

After giving birth, your brain doesn’t simply bounce back to “normal” – it continues to change. A 2022 review of 12 studies found that most research shows brain tissue growth during the postpartum period, especially in grey matter.6

These areas include:

The hippocampus: critical for memory and learning
The auditory cortex: for processing baby sounds
The amygdala: for emotional processing

One study even found that the brains of postpartum women appeared biologically younger than before pregnancy, based on machine-learning models estimating brain age.7 This suggests that pregnancy may be protective, rather than damaging, in the long term.

Pregnancy Rewires the Brain for Caregiving

The changes pregnancy brings to the brain aren’t just structural – they also affect how the brain functions, even long after giving birth. In fact, early motherhood may sharpen certain cognitive systems, making the brain more responsive, emotionally attuned and potentially more resilient over time.

A 2023 study used advanced brain imaging to examine how mothers’ brains work at rest – not just at moments of caregiving, but behind the scenes. Compared to women who had never been pregnant, mothers showed more flexible and efficient communication between brain areas involved in emotion, memory and decision-making.8

The changes were concentrated in what's known as the parental caregiving network, which includes:

The amygdala: for emotional regulation
The nucleus accumbens: for reward and motivation
The parahippocampal gyrus: for memory and context

Together, these areas support the intense mental balancing act of motherhood; sensing, reacting, soothing and planning (often all at once).

Importantly, mothers who felt more positive about their parenting experience showed more responsive brain networks. In other words, our emotions are deeply connected to how our brains function, and vice versa.

Is Baby Brain Real?

Yes. But not in the way most people think.

Up to 80% of new mothers report memory and attention difficulties.1 Meanwhile, research shows that pregnant women experience slightly slower processing speeds and reduced cognitive flexibility, especially in the third trimester.9

However, these changes are usually subtle and temporary and do not affect intelligence or long-term cognitive ability. More often, what women experience as “baby brain” is shaped by mental load, stress, disrupted sleep and social messaging, rather than the brain structure itself.

Perhaps more importantly, the stereotype of baby brain might be doing more harm than good. A 2022 review argued that the stereotype of baby brain may reinforce itself.10 When women are told to expect forgetfulness, they may be more likely to experience or notice it; a phenomenon known as stereotype threat.

So yes, baby brain exists, but the narrative around it needs a serious update. You may feel foggy or scattered during pregnancy, but it’s not a sign of failure. It’s a sign your brain is working harder than ever to navigate an emotional, cognitive and physical transformation.

Does Pregnancy Change Your Brain Long-Term?

Two major studies looking at the health of older women support the idea that pregnancy leaves a lasting impact on the brain.

In the Rotterdam Study, women who had given birth showed significantly larger total grey matter volumes later in life than women who hadn’t – even after accounting for age, education, and health status.11

Another study using UK Biobank data involving over 36,000 women aged 45–82 found that mothers had higher grey matter density than non-mothers, especially in areas linked to sensory processing and decision-making.12 These effects were not seen in fathers, and not observed in women who had been pregnant but not parented (e.g. pregnancy loss or stillbirth), suggesting that both biological and caregiving factors play a role.

While these long-term brain changes didn’t predict more happiness or distress directly, mothers were more likely to report a stronger sense of meaning in life, pointing to psychological as well as neurological shifts.

So, pregnancy and motherhood specifically seem to have permanent, lasting effects on the brain.

Beyond Hormones: What Else Affects the Brain in Pregnancy?

Hormones are a major driver of brain plasticity in pregnancy. Oestrogen, progesterone, oxytocin, and prolactin all interact with brain receptors and influence neural growth, stress response, and emotional sensitivity.

But hormones aren’t the whole story. Other powerful influences include:

The placenta

Often overlooked, the placenta produces neurotransmitters such as serotonin and dopamine, which shape fetal brain development and may also affect the maternal brain.13 This is known as the ‘placenta-brain axis’, a direct biochemical link between pregnancy and the mother’s brain.

Fetal microchimerism

Fetal cells can cross the placenta, into the mother’s bloodstream and embed themselves in the mother’s brain, liver, and other organs.14 These cells can persist for decades, and while their role isn’t yet fully understood, researchers suspect they may help with immune response, tissue repair, or long-term brain health.

The act of caregiving

Caregiving is mentally demanding: constant planning, multitasking, emotional regulation, and decision-making (essentially, high-level cognitive work). This kind of mental stimulation mirrors what neuroscientists call an “enriched environment”, which is known to support long-term brain health and delay cognitive ageing.

Making Sense of the Evidence

So what does all this research really mean – not just for science, but for your lived experience?

Here’s the big picture so far:

Pregnancy and motherhood reshape the brain in consistent, measurable and often long-lasting ways.
These changes are an adaptation, not a decline. The shifts in structure and function are all part of a complex biological preparation for caregiving and emotional connection.
You’re not broken. Foggy days are real, but they’re temporary and usually reflect stress, poor sleep, or overload, not damage.
You may come out of this cognitively stronger. Postpartum growth and long-term brain health may be enhanced by motherhood, especially when supported by community and care.
These changes are long-lasting and potentially protective. From grey matter increases to a lower “brain age,” motherhood may build neurological resilience for the long haul.

It’s time to change the narrative on baby brain, it isn’t a joke or a flaw. It’s one of the most extraordinary examples of adult neuroplasticity we’ve ever observed – and we’re only just beginning to scratch the surface.

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