Dr Jessica Miller, PhD Murdoch Children’s Researcher Professor David Burgner, Murdoch Children’s Group Leader, Infection and Immunity Murdoch Children’s Research Institute Royal Children's Hospital Victoria Australia

Murdoch Children’s Reports Surprising Finding on Preterm Births During COVID Lockdown

MedicalResearch.com Interview with:

Dr Jessica Miller, PhDMurdoch Children’s Researcher
Professor David Burgner, Murdoch Children’s Group Leader, Infection and Immunity
Murdoch Children’s Research Institute
Royal Children's Hospital
Victoria Australia

Dr. MIller

Dr Jessica Miller, PhD
Murdoch Children’s Researcher and
Professor David Burgner,
Murdoch Children’s Group Leader, Infection and Immunity
Murdoch Children’s Research Institute
Royal Children’s Hospital
Victoria Australia


MedicalResearch.com: What is the background for this study?

Response: Early reports following the initial COVID-19 lockdowns showed huge variation in changes to preterm birth and stillbirth rates, deeming it difficult to understand the pattern worldwide. It was uncertain if the observed variations were due to differences in study design and methodology, immediate impacts of lockdowns or changes in health service utilization. Previous reports from single populations or facilities were unlikely to be representative of the population and could not be compared across populations. Lockdowns affected health, social and economic factors that could lead to reductions in preterm birth rates. Changes in hygiene practices and abruptions to traffic following lockdown led to alterations in non-COVID infections and air pollution, which are known to trigger inflammation and contribute to preterm birth.

Given the uncertainty in the earlier reports, we aimed to conduct a rigorous, standardised analysis using high-quality, total-population data from across the world in order to summarize and compare rates across countries. Our large global study included 52 million births between 2015-2020 from 26 countries and represents one of the first large-scale analyses of birth outcomes during the early months of COVID-19.

MedicalResearch.com: What are the main findings? True among various economic groups?

Response:  In high-income countries, we saw small reductions (about 3-4% relative change) in preterm birth rates in the first few months of lockdown, we did not observe a difference in stillbirth rates. We had much less total-population data from low- and middle-income countries, although the data from Brazil were consistent with the overall findings for preterm birth. In addition, stillbirth rates appeared to increase in Brazil initially following lockdown, which may have been related to differential access to healthcare. Consistent changes in stillbirth rates were not observed in other countries.

MedicalResearch.com: What should readers take away from your report?

Response: Annually, close to 15 million babies are born preterm worldwide. Despite the small reductions we saw in preterm birth during COVID-19 lockdown in our study, the reduction translates to a huge number of averted preterm births.
We estimated that nearly 50,000 preterm births, in the first month of lockdown alone, were averted.

MedicalResearch.com: What recommendations do you have for future research as a results of this study?

Response: It is important to understand the underlying pathways linking lockdown with the reduction in preterm births. Understanding the causal mechanisms could have huge implications for clinical practice and policy. Potential modifiable mechanisms underlying our findings that should be investigated as possible contributors to preterm birth include the possible effects of non-COVID-19 infections, air pollution, maternal stress and economic security, and access to health care. All these were likely to have been profoundly affected by the lockdowns.

MedicalResearch.com: Is there anything else you would like to add? Any disclosures?

Response: The collaborative partnership of this study, which includes 167 collaborators across 42 different countries, rapidly formed during the pandemic and highlights everyone’s eagerness to understand how mothers and babies were affected during the COVID-19 pandemic.

This work was supported by the International COVID-19 Data Alliance (ICODA), an initiative funded by the Bill and Melinda Gates Foundation and Minderoo and convened by Health Data Research (HDR) UK, in addition to support from the HDR UK BREATHE Hub.


Calvert, C., Brockway, M.(., Zoega, H. et al. Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries. Nat Hum Behav (2023). https://doi.org/10.1038/s41562-023-01522-y

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Last Updated on March 1, 2023 by Marie Benz