The number of babies born in the U.S. dropped by 4% in 2020 compared with the previous year, according to a new federal report released Wednesday. The general fertility rate was 55.8 births per 1,000 women ages 15 to 44, reaching yet another record low, according to the provisional data.

"This is the sixth consecutive year that the number of births has declined after an increase in 2014, down an average of 2% per year, and the lowest number of births since 1979," the National Center for Health Statistics said.

The U.S. total fertility rate, which estimates how many babies a hypothetical group of 1,000 women would have during their life based on data from a given year, remains far "below replacement" – meaning there wouldn't be enough babies born for a generation to exactly replace itself.

"The rate has generally been below replacement since 1971 and has consistently been below replacement since 2007," according to the agency, which is part of the Centers for Disease Control and Prevention.

The statistical replacement rate is 2,100 births per 1,000 women. But in 2020, the U.S. total fertility rate fell to 1,637.5 births per 1,000 women. One year earlier, it was just over 1,700 births.

Just over 3.6 million babies were born in the U.S. last year, according to the agency. Demographically, the number of births fell across all ethnicities and origins, according to the report, which relied on U.S. Census Bureau population estimates that were derived in July.

The provisional number of births declined 4% for both white and Black women, 3% for Hispanic women, 6% for American Indian and Alaska Native women, and 8% for Asian American women.

The birthrate didn't go up in any age group and fell in most of them. One of the largest declines was in teenagers, where the birthrate fell by 8%, to 15.3 births per 1,000 females. The birthrate for women between 20 and 24 years old fell by 6%.

The highest birthrate came from women who are 30 to 34 years old, with 94.8 births per 1,000 women. The number of women in their late 20s who gave birth fell by 5% from 2019, as their birthrate decreased to 90 births per 1,000 women. Those two age groups each gave birth to more than 1 million babies in 2020.

The number of preterm births (babies born after less than 37 weeks of gestation) declined to 10.09% — the first drop since 2014, the center said. The cesarean section delivery rate rose slightly, to 31.8% of all births.

News of the continued fall in birthrates comes as the U.S. is coping with losing nearly 580,000 people to the COVID-19 pandemic. The National Center for Health Statistics' report on births did not focus separately on the coronavirus, but it previously found a drop in the number of mothers who accessed high-quality prenatal care in 2020 compared with 2019.

Even before the pandemic, the annual population growth rate in the U.S. was seen falling to its lowest levels in the past 100 years – and the nation's falling birthrate is just one part of that equation.

The number of U.S. deaths had been rising as America's large baby boomer generation ages. And immigration, the tool that the U.S. and other countries use to compensate for an aging workforce and population declines, has fallen from the heights reached in 2016, when more than 1 million people moved to the United States.

That dynamic has shown signs of a sharp reversal in recent months as a growing number of migrants have been arriving at the U.S.-Mexico border since President Biden took office.

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