Spring no more: France’s shift in birth patterns

What’s the most common season for babies to be born?

In many European countries, it’s late summer or autumn. Births are 5% to 10% more common in these months than others.

But this seasonal pattern used to be different. The chart shows the most common month for births each year. We’ve focused on France, which has data since the 1860s.

As you can see, spring was the most common season for births then. The pattern was temporarily disrupted during the two World Wars but continued until the late 20th century. Then, births shifted to later in the year, with late summer and autumn becoming more popular.

This shift also occurred in many other European countries and North America.