Preterm births decreased slightly following the infection prevention measures at the start of COVID-19

A largescale international study shows decrease in preterm births following the infection prevention measures during the first months of the COVID-19 pandemic, including Iceland. The research findings are presented in the latest issue of Nature Human Behaviour, published today. Three scientists at the University of Iceland are part of the research team, the largest of its kind covering 50 million births worldwide.

Babies born preterm decreased and stillborn rates remained unchanged during the first four months of COVID-19 lockdowns, according to a study across 26 countries. The multidisciplinary study of 52 million births found a 3-4 per cent relative reduction in preterm births – defined as birth before 37 weeks gestation – during the first four months of COVID-19 lockdowns. But the decrease in preterm births was limited to only high-income countries. The International Perinatal Outcomes in the Pandemic (iPOP) Study, one of the largest studies of its kind, involved 167 collaborators across 42 countries, including Iceland. 

“This research represents one of the first large-scale analyses of birth outcomes during the early months of the COVID-19 pandemic,” said study co-lead Associate Professor at the University of Iceland, Helga Zoega who is an expert in epidemiology and harmonisation of big data for large-scale international collaborations in the School of Population Health at UNSW Medicine & Health. Kristjana Einarsdóttir, professor of public health sciences, and Emma Marie Swift, assistant professor of midwifery, are also part of the research team from the University of Iceland.

“Previous research relied on smaller datasets or on populations within a single socioeconomic, regional or cultural group. The scope and breadth of the iPOP dataset allowed us to thoroughly examine global birth trends during the shifting pandemic landscape,” adds Helga. 

The researchers noted the potential reasons for the decrease in preterm births may include fewer non-COVID infections due to improved hygiene practices, and reduced air pollution due to abrupt reductions in traffic during the lockdown period. Infections and air pollution are known to trigger inflammation, which contributes to preterm birth.

“In an average year, there are an estimated 14.8 million preterm births worldwide, meaning that even a modest reduction could have a large impact on global birth trends. We estimate that nearly 50,000 preterm births were averted in the first month of lockdown,” says Helga.“Understanding the underlying pathways linking lockdown with the reduction in preterm births could have implications for clinical practice and policy.” The iPOP study recorded no difference in stillbirth rates among high-income countries. The stillbirth rate in Iceland is about 2.7 per 1000 births.

Emma Marie Swift, Helga Zoega and Kristjana Einarsdóttir, all research scientists at the University of Iceland, were all a part of the research team in this largescale international study.

The research findings in Nature Human Behaviour can be found on the journal's website.

The iPOP Study is a collaborative partnership

Study co-lead Dr Natalie Rodriguez, Director of Operations, Diversity & Inclusion at the THRiVE Discovery Lab at The Children's Hospital Research Institute of Manitoba and University of Manitoba, said collaborative partnerships forged during the study would continue to strengthen and grow public health research around the globe long after the results were published. “This is a legacy dataset,” she said. “The scale of data collected during the iPOP study will be used for future research projects for years to come.”

Study co-founder Dr Meghan Azad, from the University of Manitoba, said the study was developed at an astonishing speed, particularly given the scope of the collaborative partnerships. “The iPOP study united and mobilised public health researchers in a truly unprecedented way,” she said. “This level of collaboration was grounded in a unified sense of purpose that couldn’t have happened at another period in history. Everyone was eager to do their part to support mothers and babies during a global health crisis.”

To encourage actionable policy and practice recommendations, the iPOP consortium worked closely with partners including the World Health Organization (WHO), the United Nations Population Fund, World Vision and the Public Health Agency of Canada. Helga  Zoega said it was an “incredible partnership between 167 collaborators across 42 different countries. Everyone was eager to contribute expertise and data to better understand how this global health crisis affected mothers and babies. As a population health researcher, it was highly motivating to see so many high-quality datasets come together and to work on harmonising them across countries and analytical approaches.” 

The next step includes research into causal pathways to better understand the reasons behind our findings, that is what are the underlying reasons for reductions in preterm birth during lockdowns, according to Helga. “There is already ongoing research into this on a systematic and individual level, including the role of reductions in non-SARS-CoV-2 infections, reduced air pollution and changing stress levels among pregnant people during periods of lockdown.”