Swedish Study Finds That Mild COVID-19 in Pregnant Mothers Alters Babies Genes and Impacts Long-Term Health
Nikhil Prasad Fact checked by:Thailand Medical News Team May 14, 2025 6 hours, 33 minutes ago
Medical News: Scientists Reveal How Even Mild COVID in Pregnancy Can Leave Epigenetic Marks in Newborns
In a groundbreaking new study out of Sweden, researchers have discovered that babies born to mothers who had COVID-19 during pregnancy—even if the illness was mild—may carry lasting biological changes at the genetic level. These subtle alterations could potentially affect the child’s neurodevelopment, immune responses, and long-term disease risks.
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wedish Study Finds That Mild COVID-19 in Pregnant Mothers Alters Babies Genes and Impacts Long-Term Health
This
Medical News report is based on a collaborative effort by scientists from several Swedish institutions, including Linköping University, Karolinska Institutet, Umeå University, Lund University, the University of Gothenburg, and Örebro University. The study forms part of the ongoing COVID-19 in Pregnancy and Early Childhood (COPE) project, a nationwide investigation into how the pandemic might affect children born during this unprecedented time.
Uncovering Hidden Genetic Rewrites
The researchers focused on a process called DNA methylation—a type of epigenetic modification that doesn’t change the DNA sequence itself but can switch genes on or off, much like a dimmer switch controls a light. Using sophisticated genome-wide analysis tools, the team analyzed immune cells from blood samples of infants born to mothers with and without COVID-19 during pregnancy.
Out of the 38 infants studied, 23 were born to mothers who had COVID-19 (confirmed via PCR or antibody testing) during pregnancy, while 15 served as controls. The mothers had mild symptoms and none of the babies were born prematurely or with health issues. Despite this, the researchers found more than 2,000 specific DNA methylation changes in the infants exposed to SARS-CoV-2 in the womb.
These changes affected 1,264 genes—many of them involved in brain development, immune function, and hormonal signaling pathways. Even more intriguingly, several of these genes are known to interact with the SARS-CoV-2 virus itself, suggesting a deeper biological imprint left by the infection.
When the Timing of Infection Matters
The scientists didn’t stop there. They dug even deeper to see whether the trimester during which the mother got COVID-19 made a difference. It did. Infants exposed in the first trimester showed changes linked to smell perception (olfactory pathways), while second-trimester exposure was associated with Notch signaling—a system that helps form the nervous and immune systems. Third-trimester infections triggered alterations in lysosome-related genes, which are important for breaking down cellular waste and pathogens.
These trimester-specific changes suggest that the baby’s stage of development at the time of maternal infection plays a crucial role in how their genes are affected, a finding that aligns with earlier studies on other viral expo
sures in utero.
Cord Blood Reveals Further Clues
To validate their findings, the team also analyzed umbilical cord blood cells collected at birth from a subset of the same infants. They found 894 additional methylation changes involving 501 genes. Some of these overlapped with the earlier findings from the infant blood samples, strengthening the evidence that these changes were caused by maternal infection and not post-birth environmental factors.
The altered genes in the cord blood also mapped to critical pathways, including those related to metabolism, hormone signaling, and heart function.
Real Life Implications for the Immune System
To understand whether these DNA methylation changes have real-world effects, the researchers stimulated the infants' immune cells in the lab. They used two types of SARS-CoV-2 proteins and a mitogen, a substance that provokes strong immune activity.
In babies born to infected mothers, the immune cells responded differently—specifically showing altered levels of proteins such as AXIN1, CASP8, STAMBP, and OPG. These proteins are involved in controlling cell death and inflammation, processes essential for a healthy immune system.
Interestingly, 32 of the 73 genes involved in both the epigenetic and immune responses were known to directly interact with proteins from SARS-CoV-2, emphasizing the virus’s ability to hijack and disrupt host biology at a foundational level.
What Does This Mean for These Babies' Futures
While the babies in the study appeared healthy at birth and showed no immediate signs of illness, the genetic changes identified raise red flags about potential long-term effects. Previous research has linked prenatal infections to later issues in brain development and mental health, including higher risks of autism and cognitive delays.
One hormone-related pathway affected in this study, the apelin signaling system, plays a vital role in heart function and blood pressure regulation. It is also regulated by ACE2—the same receptor used by the coronavirus to enter cells. This link suggests that even a short maternal infection may trigger a cascade of changes in the fetus that persist after birth.
Furthermore, the immune alterations observed could mean that these children might respond differently to future infections or vaccinations. Whether these differences are harmful, beneficial, or neutral remains to be seen, but the researchers stress the need for long-term monitoring.
Not All Bad News but A Strong Call for Caution
The authors of the study were careful not to draw alarmist conclusions. As Dr. Maria Lerm from Linköping University, the lead author, explained, “The global impact of these epigenetic effects is not yet known. However, the overlap of affected genes with critical developmental processes suggests a potential trade-off—possible enhanced immune resilience might come at the cost of neurodevelopmental vulnerabilities.”
This view is supported by previous studies that linked maternal COVID-19 during pregnancy to increased rates of developmental delays and behavioral issues at one year of age, especially in cases of severe infection. This new research adds biological evidence to those clinical observations, making the connection more than just coincidental.
A Wake-Up Call for Future Pandemic Preparedness
This study carries important implications not only for COVID-19 but also for future outbreaks. It reminds us that even asymptomatic or mild infections during pregnancy can leave lasting marks on the next generation. And with so many pregnant women exposed to SARS-CoV-2 globally over the past few years, these findings could help shape pediatric health monitoring and inform vaccine or therapeutic strategies.
As the COPE study continues to track the long-term development of these infants, scientists hope to answer whether these genetic changes fade over time or set the stage for future vulnerabilities.
Conclusion
The Swedish study provides compelling evidence that maternal COVID-19 infection—even in mild cases—can leave a lasting imprint on a baby’s genetic regulation through DNA methylation changes. These alterations affect genes related to brain development, immunity, and even heart function, with some directly linked to viral hijacking mechanisms. Although the infants appear healthy for now, the changes raise concerns about future health outcomes and underline the importance of closely monitoring children born during the pandemic. These findings also serve as a broader warning about the subtle and often invisible ways viruses can shape human biology across generations. As our understanding of epigenetics deepens, so too must our commitment to safeguarding vulnerable populations, especially during global health crises. Further studies are urgently needed to determine the long-term impact and whether any interventions can reverse or mitigate these early genetic imprints.
The study findings were published on a preprint server and are currently being peer reviewed.
https://www.medrxiv.org/content/10.1101/2025.05.10.25327356v1
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