Researchers from the Erasmus teaching hospital in Rotterdam believe that there was a decrease in the number of premature babies born in the Netherlands while the country was under lockdown.

A similar drop was observed during the peak of the coronavirus outbreak in other European countries including Denmark and Ireland, according to the New York Times.

Premature babies – those born before 32 weeks of gestation – are at greater risk of a variety of health problems, including neurological issues, vision and hearing problems and premature death.

Irish and Danish doctors reported a 90% drop in significantly premature babies, born earlier than 28 weeks, but the fall in the Netherlands was said to be “slight,” reports NOS.

It is unclear what was causing the decrease. Some researchers speculate that during lockdowns, pregnant women may have slept for more hours and spent less time on their feet. Others suggest that a decrease in air pollution may have played a role.