Pregnancy is often described as a time of joy and anticipation, but for many women, it can also come with some physical, emotional and financial stress. Researchers have long known that stress can affect a mother’s well-being, but new insights show it can also shape how a baby grows, develops, and even how it responds to stress later in life. A 2025 review published in Pediatric Discovery explores how maternal stress can affect everything from brain development to long-term health, using real-world examples such as natural disasters, war, and economic hardship to illustrate these effects.
When a person feels stressed, the brain activates what is known as the hypothalamic-pituitary-adrenal (HPA) axis. This system releases hormones, specifically cortisol, that prepare the body to respond to challenges. During pregnancy, these stress hormones can cross the placenta and reach the developing baby.
Cortisol isn’t always bad. in small amounts, it helps the maturation of the baby’s organs. But chronic or intense stress can flood the baby’s system with higher-than-normal levels of cortisol. Over time, this can affect the baby’s growth, brain development, and even how its own stress system works after birth.
Simply put, a baby “learns” about the outside world through the womb. If this world seems stressful, their body adjusts to expect stress, sometimes at the expense of long-term health.
The fetal brain is incredibly sensitive to its environment. Research shows that stress can change the way certain areas of the brain develop, particularly the hippocampus (which is involved in memory and learning) and the amygdala (which helps regulate emotion and fear).
In one study, babies whose mothers experienced high stress during pregnancy had smaller hippocampal volumes on MRI scans. Others showed altered connections between the amygdala and other brain regions, which could affect emotional regulation and behavior later in life.
Interestingly, the type of stress and the timing during pregnancy seem to matter. Stress in early pregnancy can affect physical development – such as smaller head circumference and lower birth weight – while stress in later stages can have a greater impact on emotional and behavioral development.
Scientists are also learning that stress can change the way certain genes work. When a mother experiences chronic stress, her body releases more glucocorticoids, hormones that, in high amounts, can affect the protective barrier of the placenta. This allows more cortisol to reach the baby, which can change the way genes involved in the stress response are expressed.
This process, called ‘epigenetic programming’, does not change the DNA itself, but turns certain genes on or off. These changes can affect how a child responds to stress for the rest of their life. For example, babies exposed to high stress in the womb may grow up to have higher cortisol levels and more anxiety.
This shows that the effects of stress don’t stop at birth – they can ripple through generations.
Lessons from natural disasters
To understand how stress affects pregnancy in real-world situations, scientists often study natural disasters where large groups of people experience sudden, severe stress.
Project Ice Storm (Canada, 1998)
Pregnant women who experienced a massive ice storm were followed for years after giving birth. Those who experienced the highest levels of stress had babies with lower birth weight and later children with greater emotional reactivity and cognitive challenges.
2010 Earthquake in Chile
Pregnant women during this devastating earthquake gave birth to babies with smaller head circumferences and shorter lengths. Years later, some of these children showed delays in motor and cognitive milestones, reinforcing that early exposure to stress can have lasting consequences.
2008 Iowa Floods
Prolonged flooding offered another perspective. Mothers who experienced constant stress had babies with weaker immune systems and greater sensitivity to stress. These findings show that both short-term trauma and chronic stress can affect how babies develop and respond to the world around them.
When stress becomes intergenerational
The review also highlights how stress doesn’t just affect one generation. In places affected by war or chronic violence, such as the Democratic Republic of Congo and Gaza, maternal stress has been linked to changes in DNA methylation, a biological process that can affect gene function.
These changes were found in both mothers and their babies, suggesting that trauma can be “transmitted” biologically. This may explain why children and even grandchildren of trauma survivors sometimes show higher rates of anxiety, depression, and stress-related disorders.
It is a reminder that maternal health and safety are deeply connected to the long-term health of families and communities.
The mental health connection
Maternal stress often goes hand in hand with anxiety and depression. Research shows that when mothers experience significant stress, it can alter brain development in the fetus. In some cases, the left side of the hippocampus may be smaller, while other areas of the brain show more folding or “twisting,” which can affect thinking and emotional processing.
Children born to mothers with high stress or anxiety during pregnancy are more likely to experience behavioral challenges such as hyperactivity, attention difficulties and mood regulation problems. These effects may persist into adolescence if not treated early.
The good news is that not all effects are negative or permanent. Many of these outcomes can be addressed with strong postpartum support, early intervention, and consistent emotional care.
Stress and access to health care
THE Pediatric Discovery The review also looked at health data from Georgia’s OASIS database, which tracks maternal and infant health outcomes between 2013 and 2023. While the total number of pregnancies remained stable, fetal and infant mortality rates declined over the decade.
These improvements were associated with better access to maternal and infant care. Simply put, when mothers receive consistent care during and after pregnancy, whether through regular checkups, mental health support, or newborn follow-up visits, babies tend to have better outcomes.
However, the data also showed persistent inequalities. Socioeconomic inequality, limited access to health care, and racial disparities continue to heighten stress levels in marginalized communities. This makes addressing maternal stress not only a medical issue but also a social justice issue.
Understanding how stress affects fetal development gives parents, health care providers, and policy makers an opportunity to intervene. Here are some research-backed strategies:
- Mindfulness-Based Stress Reduction (MBSR): Techniques such as meditation and guided breathing have been shown to reduce stress and lower cortisol levels during pregnancy.
- Cognitive Behavioral Therapy (CBT): Talking with a therapist can help mothers reframe stressors and manage stress.
- Social Support Networks: Strong family and community support can act as a protective buffer against chronic stress.
- Access to Care: Expanding prenatal and mental health care, especially in underserved areas, helps reduce disparities in birth outcomes.
By focusing on prevention and support, it is possible to improve not only the health of pregnant women but also the lifelong health of their children.
The research was reviewed in Pediatric Discovery it reinforces something simple but profound: a mother’s environment shapes her baby’s future. Stress during pregnancy is not just an emotional burden. It’s a biological signal that can affect how a child grows, learns, and even handles stress itself.
Although not all stress can be avoided, understanding its effects enables families and health care systems to act early. Whether it’s providing better mental health support, building stronger communities, or advocating for policies like paid parental leave, addressing maternal stress is one of the most important ways to invest in the next generation.
