The birthrate in America fell 4 percent last year, marking the biggest annual decrease in almost half a century — suggesting the coronavirus pandemic has accelerated an already existing trend.

While some jokingly predicted a baby boom when the pandemic first struck — as couples were stuck at home in isolation — many experts suggested the reverse might happen as anxiety about coronavirus, massive job loss and the disruption to society caused Americans to postpone or think twice about having a child amid the chaos.

The country’s fertility rate in 2020 stood at 55.8 births per 1,000 women in the ages 15 to 44.

The falling birthrate combined with the sharp increase in deaths caused by the pandemic, could cause a marked aging of the country’s population if the decline continues to bear out in subsequent years, experts say.

The birthrate for women ages 20 to 24 fell 6 percent from 2019.

By contrast, last year the birthrate for women ages 40 to 44 had been risen almost continuously since 1985 by an average of 3 percent as Americans increasingly chose to have children later in life.