We're not having many more babies. But we are having them differently. ( Photo by Flickr user gabi menashe )

As teen birth rates plummet, women in their thirties and forties appear to be driving America’s baby bump -- but don’t expect the recent uptick to become an upswing.

Births in the United States rose by 53,743 from 2013 to 2014, the first increase in seven years, following a stretch of decreases since the recession, according to the National Center for Health Statistics.

Steven Martin, who studies social demography at the Urban Institute, said the country isn’t necessarily entering a time of tremendous growth or even exiting what he calls the “baby recession.”

The slightly higher number of births, he said, can probably be attributed to a larger population of women in their childbearing years. The birth rate, or annual number of births per 1,000 of the population, hasn’t significantly budged: 53,743 more births represents a 1.4 percent relative increase in fertility, according to the Urban Institute.

Last year, to put our current amount of tiny human creation into perspective, 3,985,924 babies were born, compared with 3,932,181 in 2013. That’s still 330,309 fewer births than the 4,316,233 in 2007, before the recession rocked household budgets.

The latest numbers more realistically reflect a “new baby normal,” Martin said, or a slow transformation of what the average American mom nowadays looks like. In previous decades, she was much younger, either in her late teen years or early twenties. Now she’s closer to 30, married and more likely to be adding to her family by choice and not surprise.

The long-term implication, Martin said: “If family formation keeps moving  to older ages, U.S. fertility could decrease even more in the future.”

In 1991, for example, teens gave birth at a rate of 61.8 per 1,000 women between ages 15 and 19. Last year, that rate fell to 24.2 births per 1,000 women.

Last year, 40 percent of births arrived to unmarried mothers, a slight dip from the 41 percent share seen since 2008, and only the third one-year decrease in this measure since World War II, according to the Pew Research Center. (The last drop happened in 1995.)


Courtesy of the Pew Research Center

Family formation rates for women 25 to 29, meanwhile, have actually declined. Millennial women have been the slowest generation of potential moms to start having babies. First birth rates for women age 30 through 34, and 35 through 39, however, increased fr om 2013 to 2014. Now, 43 percent of births are to women older than 30. In 2000, that share was only 36 percent.


Courtesy of the Urban Institute

The reasons are complicated: More young women than ever have access to birth control. They’re also outpacing men in college enrollment and dominating nearly half of the workforce.

This miniature birth boost comes with a healthier economy; babies, after all, are expensive. But moms who gave birth last year weren’t overwhelmingly bringing their first bundle of joy into the world. Many of these new babies already have older sibling.

“A lot of women in couples started having families before the recession and just put the brakes on when times got hard," Martin said. "These families just started having children again.”