The results suggest that 50,000 fewer babies were born prematurely – before 37 weeks of pregnancy – than had been expected after the initial Covid 19 lockdown.
The findings are based on data comparing 56 million births from 26 countries between January 2015 and July 2020.
Experts say the drop could be linked to pregnant women being exposed to fewer non-Covid-19 infections and better air quality, because of reduced traffic, during lockdown.
Infant mortality
On average worldwide there are an estimated 14.8 million preterm births each year. Related complications account for 35 per cent of newborn deaths, making it the leading cause of infant mortality globally.
Researchers also investigated whether declining numbers of preterm births could potentially lead to higher numbers of stillbirth. Some babies are delivered intentionally early to save their lives and any reduction in this intervention could result in a rise in stillbirths.
Covid-19 impact
The team found that high income countries experienced no change in stillbirth rates. However, data from Brazil showed an increase in stillbirth rates during the second, third and fourth months of their lockdown.
The shift in some countries could be because of delayed or reduced access to quality healthcare during the early stages of the pandemic or other factors related to Covid-19 lockdowns, experts say.
The research was part of the International Perinatal Outcomes in the Pandemic (iPOP) Study, which investigates the impact of pandemic lockdowns on preterm births and stillbirths worldwide. iPOP is a collaboration between 167 global partners including the University of Edinburgh.
The team say the data should be interpreted with caution as it is highly skewed towards high-income countries due to the lack of data available from low- and middle-income countries.
This study represents a huge global collaborative effort and we were able to show decreases in preterm births in the first few months of the Covid-19 lockdowns across many countries, providing a strong indication that lockdown played a role in these reductions.
Dr Clara Calvert
Chancellor’s Fellow at the University of Edinburgh’s Usher Institute
Now the challenge is to understand why preterm births fell. Infections are a cause of preterm births, and we know that non-Covid-19 infection rates dropped during periods of lockdown. However, changes in other factors that are linked to preterm birth, such as air pollution and maternal workload, may also have contributed.
Professor Sarah Stock
Consultant obstetrician and Professor in Maternal and Fetal Health at the University of Edinburgh’s Usher Institute
The findings are published in the journal Nature Human Behavior. This work was supported by the International COVID-19 Data Alliance.
