This Mother’s Day, odds are that the new mother pushing the stroller has a few more years on her than in years past.
A federal survey being released Friday finds that the percentage of first-time mothers 35 or older has risen more than fivefold since the early 1970s, a trend toward “midlife moms” that demographers and social scientists say is having pronounced effects on the size, composition and future growth of the U.S. population.
The numbers are even more pronounced for the subset of women having their first child after 40. In 1970, an average of 0.4 women out of every 1,000 women waited until their 40s to have a first baby. By 2012, the average jumped to 2.3 women.
The trend toward older motherhood has pros and cons — medically, politically and socially — analysts say.
Births to women at older ages, especially at 40 and beyond, are associated with higher health risks for the infants and the mothers, although medical professionals say treatments and outcomes have improved in recent years.
On the positive side, older mothers are likely to have higher educations and higher incomes than their younger counterparts, as well as more outside resources.
Hollywood is following the trend. First-time mothers older than 40 include actress Halle Berry, model Cheryl Tiegs and singer Mariah Carey.
When women give birth later in life, he said, they are less likely to have multiple children. Moreover, the timing of births has a ripple effect in the size and age of the national workforce and the elder population.
When paired with a falling teen mother birthrate over the same period, the survey finds that the average age for all first-time mothers in the United States has crept up by nearly five years in barely more than two generations. Women on average are 25.8 years old when they first give birth, compared with 21 in 1970.
The upward trend of first births to older mothers has been almost steady, Mr. Mathews said.
For women in their late 30s, “there was one drop for a few years,” from 2008 to 2010, but the rate started to increase again in 2011 and 2012, he said. Rates for women in their early 40s have risen slowly but steadily since 1985.
Put another way, in 1970, the federal government reported 14,146 births to women older than 35. In 2012, that number was around 133,000.
The reasons for older motherhood are not mysterious: Women pursuing higher education and careers tend to delay marriage and childbirth.