More US Moms Waiting Until Late 30s to Have Kids Birth rates for those 35 and older rising sharply By Kevin Spak, Newser Staff Posted May 9, 2014 7:11 AM CDT 25 comments Comments (Shutterstock) (Newser) – More and more Americans are waiting to have kids until they're in their late 30s or even 40s, according to a recent Pew study and CDC figures released today. In 2012, 15% of first-time moms were over age 35, up from just 1% in 1970, the Wall Street Journal reports. The trend has accelerated since 2000, one demographer tells the New York Daily News. Since then, first-time birth rates for women age 35-39 have risen in 46 states, and those for women 40-44 have risen in 31. "This is good news," one sociologist says. Older moms "are more protected against the shock of earnings loss, and they’re probably more independent and better-established in their relationships." But there are downsides: Women who wait face more health risks, and are likely to have smaller families. That will drive down the country's already shrinking fertility rate, which can dampen economic growth.