Premature births fell during some Covid lockdowns, study finds

Nearly 50,000 preterm births could have been averted in a group of mostly high-income countries in just one month.

Elizabeth Decker had a stressful second pregnancy, plagued by daily vomiting and worry that this baby, like the first, would raise her blood pressure dangerously high and have to deliver prematurely. Funnily enough, the most relaxing part was her final trimester, which rode the world's descent into the Covid lockdown in the spring of 2020.

Ms. Decker, who is 36 and lives in North Reading, Mass., has decided to quit her high-pressure job as a lawyer and stay home. Her husband, a teacher, started working from home around this time, teaching online. He cared for their toddler and took care of meals while Mrs. Decker rested and slept. "I was able to really do nothing for the last three months of my pregnancy," she said. The spike in blood pressure her doctor had expected didn't come until late June, a week after Ms. Decker's due date, when she delivered a healthy baby.

An ambitious global childbirth study suggests Ms Decker wasn't the only parent-to-be to avoid the experience of premature birth in the early months of lockdown. The study, published Monday in the journal Nature Human Behavior, showed that in a group of mostly high-income countries – such as the United States, Belgium, Canada, Chile, Denmark and Switzerland – in the spring of 2020, there were about 4% fewer preterm births than expected. Globally, the study authors estimated that the change most likely added up to nearly 50,000 premature births averted in the first month of lockdown alone.

The discovery could help researchers better understand the causes of preterm birth, which remain frustrating to medical science.

"This is an experiment unique natural environment, where the whole world experienced this pretty drastic lockdown at the same time,” said Meghan Azad, associate professor of pediatrics and child health at the University of Manitoba and one of the study leaders. "So it was a great opportunity to look at what this might mean for mother-child health."

Back when Ms. Decker was in charge of her full-term baby, doctors in various countries were also seeing fewer premature babies than they had expected. Their observations, shared before the peer review but officially published since, were striking: in Denmark, for example, the number of the smallest premature babies had fallen by 90%. In a hospital in Ireland, very early births dropped by three-quarters or more.

The Irish authors speculated that pregnant women locked at home could experience less stress, less air pollution, or fewer viral or bacterial infections, which could reduce their chances of early delivery.

Responsive to Irish study on Twitter, Dr Azad wondered aloud - morbidly, she admitted - if doctors were seeing a drop in premature births this spring because some of those babies had been lost to of a stillbirth or miscarriage.

Within two days, Dr. Azad was teaming up with other scientists to study this issue. "It was that kind of crazy moment," she said. “A handful of researchers have had a lot of time off because their projects have been slowed down or their conferences have been cancelled. They were free to dive into a large-scale side project.

The collaboration eventually grew to include over 100 scientists from around the world and 52 million births . Using data from 2015 to 2020, scientists modeled the expected number of premature births and stillbirths during the first months of each country's strict lockdown by...