SALT LAKE CITY — Just two states — South Dakota and Utah — had a total fertility rate above replacement level in 2017, according to a new federal report.

Overall, the U.S. total fertility rate is 1,765.5 births per 1,000 women, compared to 2,227.5 in South Dakota and 2,120.5 in Utah.

The replacement rate — the number of births needed to maintain the population at its existing level — is 2,100 births per 1,000 women, or an average rate of 2.1 births per woman. It is often invoked in discussions of economic growth and having enough young workers to support an aging population.

The data, from the Centers for Disease Control and Prevention's National Center for Health Statistics, used birth certificates to calculate each state's total fertility rate, then broke the data out for the three largest race populations: non-Hispanic white women, non-Hispanic black women and Hispanic women.

The Beehive State had the highest total fertility rate for white women, at 2,099.5 per 1,000 women.

The total fertility rate (TFR) is a projection of how many births 1,000 women would have in their lifetimes, based on the age-specific birth rates. TFR is a tool used by planners and others to calculate potential growth, derived by adding up five-year age specific birth rates, then mulitiplying by five.

Demographic experts who follow national birth numbers say there's a real question about what recent numbers mean long-term.

On one hand, birth rates have been declining in most populations, but especially among teens. "Most think it's great that teen births are down," said Samuel Sturgeon, president of Demographic Intelligence.

Less clear, though, he noted, is whether recent numbers indicate people are simply delaying having children or foregoing having children entirely. Those are two very different stories with separate potential impacts.

Sturgeon calls delayed birth, for example, a "micro/macro" issue, meaning that while one might worry delaying births overall could have negative impact on the larger economy or job market for everyone in the future, for example, "it might at the same time look exactly like the kind of advice one would give a close friend or relative: 'Wait until you're ready.'"

Data highlights

  • The District of Columbia had the lowest total fertility at 1,421.0, well below replacement rate, the report says. DC was also lowest in the total fertility rate for white women, at 1,012 per 1,000.
  • Maine had the highest fertility rate for black women (4,003.5), while Alabama was highest among Hispanic women (3,085). The lowest rates for Hispanic women were found in Vermont (1,200.5) and Maine (1,281.5).
  • Among white women, the report said, Utah's rate was more than double the District of Columbia's. The Utah rate hovered right around replacement rate.
  • And California, which the report said had the most births in terms of raw numbers, "was consistently among the lowest reported (rate) overall and for each group by state."
  • The report noted potential limitations, including a small number of births within some groups. "The TFRs reported here, particularly the highest or lowest rates for a given race and Hispanic-origin group, may reflect a relatively small number of births and population size for a given state," it said.

What it means

With declining fertility, populations shrink if migration doesn't bolster the numbers, said Pamela Perlich, director of demographic research at the University of Utah's Kem C. Gardner Policy Institute.

She pointed to Utah's open economy, where the population has continued to grow despite a smaller birthrate because people have moved into the state. In some other places in the world that have shrinking fertility and less in-migration, like Japan, the older population can outnumber the younger population. Sometimes, a place's demography gets out of balance, which can have "pretty profound implications."

How a society fares involves many factors, including resources, policies and what people value, she added.

<strong>One of the big stories about why the total fertility rate has been declining nationally is near-eradicaton of teen pregnancy.</strong> – Pamela Perlich, director of demographic research at the University of Utah&#39;s Kem C. Gardner Policy Institute

What's happening with this generation of women and fertility may only become clear as a look back after the women have completed their fertility, Sturgeon told the Deseret News.

For example, one might expect that an average of 1.8 births per woman could mean most women have given birth at least once. At the moment, though, 40 percent of births are first births and 60 percent are second or later births. One has to look closely to see that women who are having children are averaging 2.5 children, while a growing number of women are having zero children, Sturgeon said.

Perlich said a breakdown of birth data by the age and race of the mother might be more telling than general data to show what's going on in a state. For example, births to immigrants may bolster fertility and birth rates. Perlich said recent Utah data has shown higher birthrates among young Hispanic women compared to white women of the same age. Around age 25 and older, that reverses.

That's what the new CDC data shows, as well.

"One of the big stories about why the total fertility rate has been declining nationally is near-eradicaton of teen pregnancy," Perlich said.

But total fertility could also climb back up when women who are now aged 20-24 and not having children do have them when they become 30-34. And recent postponement has also taken place within the context of a bigger national picture, which could change. "Part of the reason postponement has taken place is the effect of the recession," she said.

Other changes also impact numbers. For example, Utah's average age at which women marry for the first time has climbed. That fact, along with how many children they have and when, will impact birth data.

The size of a state also matters. For instance, while South Dakota outpaced Utah in total fertility rate for 2017, Utah women had nearly three times the raw number of births: 48,585 according to the report, compared to 12,134 in South Dakota.