America’s baby bust isn’t over. The nation’s birthrates last year reached record lows for women in their teens and 20s, a government report shows, leading to the fewest babies in 32 years.

The provisional report, released Wednesday and based on more than 99 percent of US birth records, found 3.788 million births last year. It was the fourth year the number of births has fallen, the lowest since 1986 and a surprise to some experts given the improving economy.

The fertility rate of 1.7 births per US woman also fell 2 percent, meaning the current generation isn’t making enough babies to replace itself. The fertility rate is a hypothetical estimate based on lifetime projections of age-specific birthrates.


Whether more US women are postponing motherhood or forgoing it entirely isn’t yet clear.

If trends continue, experts said, the United States can expect labor shortages, including in elder care when aging baby boomers need the most support.

‘‘I keep expecting to see the birthrates go up and then they don’t,’’ said demographer Kenneth M. Johnson of the University of New Hampshire’s Carsey School of Public Policy.

He estimates 5.7 million babies would have been born in the past decade if fertility rates hadn’t fallen from prerecession levels.

‘‘That’s a lot of empty kindergarten rooms,’’ said Johnson, who wasn’t involved in the report.

Other experts are not concerned, predicting today’s young women will catch up with childbearing later in their lives. The only two groups with slightly higher birthrates in 2018 were women in their late 30s and those in their early 40s.

‘‘Our fertility rates are still quite high for a wealthy nation,’’ said Caroline Sten Hartnett, a demographer at the University of South Carolina.

American women are starting families sooner than most other developed nations, according to other research. Other countries are seeing similar declines in birthrates.


Young Americans still want to have children, but they don’t feel ready to have them yet, said Karen Benjamin Guzzo, who studies families at Bowling Green State University in Ohio.

The United States could do more to encourage childbearing with parental leave, preschool expansion, and child care subsidies, and other policies aimed at helping young adults struggling with student loan debt and housing costs, Guzzo said.

Brandy Loshaw, 39, of Webster, N.Y., said that despite a stable career as a dental hygienist, ‘‘I would never be able to afford the added expense of a child and live comfortably.’’