This is good news that has not yet found a scientific explanation. In most countries of the world, February-April was the period during which population lockdowns were held. The American newspaper the New York Times recently recounted an astonishing medical fact observed by health professionals in several maternities around the world (taken up in France by our colleagues from Slate). The number of premature births likely declined during the respective lockdowns.
At the University Maternity Hospital Limerick in Ireland, no premature babies were born during the period January to April 2020, whereas in normal times this represents 3 births in 1000. This strange finding was also observed in Canada, Australia and the United States, where doctors have not yet found a rational explanation for this phenomenon.
It is true that the health crisis has brought its share of anxiety for pregnant women, especially during childbirth which could not take place normally. However, it would appear that the confinement itself may have had a positive impact in reducing premature births. Indeed, even if it is still only a question of simple assumptions, this unexplained phenomenon could have a link between the decrease of stress and pressure at work which pregnant women are confronted with in normal times. Falling air pollution could also have played a role.