Emerging research reveals a complex story of unique vulnerabilities and important protective measures during pregnancy.
Imagine navigating the thrilling yet vulnerable journey of pregnancy during a global pandemic. This was the reality for millions of expectant mothers when COVID-19 emerged, creating a wave of uncertainty through obstetric clinics worldwide.
Initially, the data seemed reassuring, suggesting pregnant women faced similar risks as the general population. However, as scientists raced to understand this novel virus, a more nuanced picture emerged—one where pregnancy itself created unique vulnerabilities to severe illness, and where infection could significantly impact both maternal and fetal outcomes.
Pregnancy induces a remarkable state of immunological adaptation. To accommodate a fetus that is genetically distinct, the maternal immune system undergoes significant changes that prevent rejection of the pregnancy. This necessary modulation, however, can also alter the response to certain pathogens, including SARS-CoV-2 1 .
The physical demands of pregnancy place substantial stress on the cardiorespiratory system. As the uterus expands, it pushes up on the diaphragm, reducing lung capacity and making it harder to clear respiratory infections.
The virus that causes COVID-19, SARS-CoV-2, gains entry into human cells by binding to the ACE2 receptor, a protein found on the surface of many cell types. ACE2 is abundantly expressed in the placenta and the respiratory tract, creating a potential pathway for the virus to cause trouble at the maternal-fetal interface 1 2 .
In 2021, a major systematic review and meta-analysis published in the Canadian Medical Association Journal provided the first comprehensive look at the data. The study synthesized evidence from 42 studies involving an astounding 438,548 pregnant individuals 1 .
Perhaps the most critical finding was the dramatic effect of disease severity. The risks were not evenly distributed; they were concentrated overwhelmingly in those who developed severe COVID-19.
These numbers translate to real-world consequences: more emergency C-sections, more tiny babies in the NICU, and more lifelong health challenges that can originate from a preterm birth or a preeclamptic pregnancy.
While the direct health effects of the virus are critical, the pandemic's indirect effects, driven by policy changes, have also been profound. A revealing 2025 retrospective quasi-experimental study in Iran analyzed how shifts in healthcare delivery during the pandemic impacted birth outcomes over four years 3 .
The researchers treated the onset of the pandemic and its associated policy changes as a natural experiment. They gathered data on 221,866 singleton births from a 48-month period (24 months before and 24 months after the pandemic began in Iran).
Their goal was to see how outcomes like preterm birth (28-37 weeks), low birth weight (1000-2500 g), and stillbirth were affected 3 .
Using a sophisticated statistical approach called Interrupted Time Series Analysis (ITSA), they were able to distinguish between pre-existing trends and changes that could be directly attributed to the pandemic policies.
These policies included a shift to virtual antenatal care, longer intervals between in-person visits, and the redirection of healthcare resources toward COVID-19 response 3 .
The study revealed several unintended, and often negative, consequences of these policy shifts.
While the short-term trend for preterm birth showed a slight decrease, the long-term data indicated that the underlying rate continued to increase, just at a gentler slope 3 .
The analysis showed that the rate of low birth weight in full-term infants (over 37 weeks) was already on an increasing trend before the pandemic. Immediately after the policy changes, there was a sharp increase, and the trend continued to rise afterward 3 .
The researchers connected these findings to inefficiencies in social and economic policies that affected financial security and access to nutrition for pregnant families, exacerbated by the crisis 3 .
This study highlights a crucial lesson: public health crises can harm maternal and neonatal health not just through the disease itself, but also through the disruption of essential healthcare services and the weakening of social safety nets.
The research on risks naturally leads to a critical question: how can we protect pregnant women and their babies? Medical professionals have developed clear strategies.
Despite the proven benefits, vaccine hesitancy remains a significant challenge. A 2025 qualitative study in Malaysia identified key barriers 5 :
Conversely, the main factors that encouraged vaccination were concern about the effects of COVID-19 infection, trust in the vaccine, and positive personal or shared experiences with it 5 .
Risk reduction of severe disease with antiviral treatment in high-risk outpatients 4
The story doesn't end at birth. Researchers are now investigating the potential long-term implications for children who were exposed to maternal COVID-19 in the womb.
Maternal infection can trigger an inflammatory response; the release of inflammatory cytokines may cross the placental barrier, potentially disrupting fetal brain development 6 .
Placental dysfunction caused by inflammation can lead to intrauterine growth restriction or hypoxia, which may affect long-term neurological and respiratory health 6 .
Ongoing, long-term monitoring of these children is essential to understand the full scope of the virus's impact and to ensure they receive the support they need to thrive.
The journey to understand COVID-19's impact on pregnancy has been one of evolving knowledge. From initial uncertainty, a clear consensus has emerged: COVID-19 poses a significant threat to maternal and fetal health, increasing the risk of preeclampsia, preterm birth, and stillbirth.
The silver lining is that this knowledge empowers action. Through a combination of evidence-based treatments, safe and effective vaccination, and the maintenance of strong prenatal support systems, we can mitigate these risks. The scientific legacy of this challenging period is a deeper understanding of how to protect the most vulnerable, ensuring healthier outcomes for generations of mothers and babies to come.
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