The birth rate in the United States fell 4% in the largest single-year drop in nearly 50 years, according to a government report.

The rate has fallen for mothers of all major races and ethnicities, and in almost all age groups, falling to the lowest since federal health officials began tracking it over a century ago. , according to the report due for release Wednesday.

Births have been declining among younger women for years as many postponed motherhood and had smaller families.

Birth rates for women in their 30s and 40s have been rising steadily. But not last year.

The United States was once among the few developed countries to have a fertility rate above 2.1 children per woman, which ensured that each generation had enough children to replace itself.

But the rate has been slipping for more than 10 years, and last year fell to around 1.6, the lowest rate on record.

“The fact that you’ve seen a decline in births, even for older mothers, is quite striking,” said lead author of the report, Brady Hamilton, of the US Centers for Disease Control and Prevention.

The numbers suggest that the current generation will not have enough children to replace themselves.

The CDC report is based on a review of over 99% of birth certificates issued last year. The findings echo a recent Associated Press analysis of 2020 data from 25 states showing births dropped during the coronavirus outbreak.

The pandemic contributed to last year’s big decline, experts said. Anxiety about Covid-19 and its impact on the economy has likely led many couples to believe that now is not the right time to have a baby.

But many of the pregnancies in 2020 began long before the American epidemic. CDC researchers are working on a follow-up report to better analyze how the decline unfolded, Hamilton said.

Other highlights of the CDC report include:

  • About 3.6 million babies were born in the United States last year, up from about 3.75 million in 2019. When births were booming in 2007, the United States recorded 4.3 million births.

  • The birth rate in the United States has fallen to about 56 births per 1,000 women of childbearing age, the lowest rate on record. The rate is half of what it was in the early 1960s.

  • The birth rate of 15-19 year olds fell 8% from 2019. It has fallen almost every year since 1991.

  • Birth rates fell 8% for women of Asian and American descent; 3% for Hispanic women; 4% for black and white women; and 6% for mothers who were Native American or Alaska Native.

  • The rate of cesarean delivery increased slightly to around 32%. It was generally declining since 2009.

  • The percentage of infants born small and premature – within 37 weeks of gestation – declined slightly to 10% after increasing for five years in a row.