Data from a nationwide Pew Research Center survey and information from the National Center for Health Statistics and the Census Bureau show that today’s mothers of newborns are older, better educated, less likely to be white and less likely to be married than their counterparts were in 1990.

There were more births to teenagers in 1990 than to women ages 35 and older. By 2008 (the latest date for which data is available), things had changed: 14 percent of births were to older women and 10 percent were to teens. Across all major race and ethnic groups, the rate of births to women ages 35 and older grew 64 percent between 1990 and 2008.

Also released as part of a report (The New Demography of American Motherhood) on the above findings were results from a 2009 Pew survey on attitudes toward these and other birth-related trends. The data were taken from a nationally representative sample of 1,003 adults that included parents, people who intend to become parents and people who do not intend to have children.

As taken from the Pew report, some of the main findings of the survey on fertility attitudes and trends include:

  • 35 percent of parents cited the reason “It wasn’t a decision; it just happened” as very important and 12 percent as somewhat important in the decision to have their first or only child.
  • Women (51 percent) were somewhat more likely than men (42 percent) to say that “it just happened” was somewhat or very important.
  • Forty-six percent said two children was the ideal number for a family; 26 percent said three; 9 percent said four; and 3 percent each said zero, one or five or more. Among parents of three or more children, 33 percent said two was ideal.
  • Nearly two-thirds of Americans (65 percent) said the growing number of single women having babies is bad for society. Only a minority disapproved of more women having babies after age 40 (33 percent), more women undergoing fertility treatment in order to have a baby (28 percent) and more women not ever having children (38 percent).
  • Most adults said they knew at least one woman who had a baby while she was not married and one man who fathered a child while he was not married. A third said they knew a woman who had fertility treatment in order to get pregnant.

Population changes

In their report on the results, Pew Researchers Gretchen Livingston and D’Vera Cohn discussed some of the factors related to the findings. They identified population changes as key factors influencing birth patterns in recent decades. There are fewer women in the prime childbearing years now than in 1990, as the youngest Baby Boomers have aged into their mid-40s. But changes in the race and ethnic makeup of young women - mainly, the growth of the Hispanic population, which has higher birth rates than other groups - have helped keep birth numbers relatively level.

Another influence on births cited by the researchers is the nation’s growing number of immigrants, who tend to have higher birth rates than the native-born (although those rates have declined in recent years). The share of births to foreign-born mothers - 15 percent of U.S. births in 1990 - has grown at least 60 percent through 2004. Births to foreign-born women in 2004 accounted for the majority of Hispanic (61 percent) and Asian (83 percent) births.

According to Pew Research Center population projections, 82 percent of the nation’s population growth through 2050 will be accounted for by immigrants who arrived in the U.S. after 2005 and their descendants, assuming current trends continue. Of the 142 million people added to the population from 2005 to 2050, the projections say, 50 million will be the children or grandchildren of new immigrants.

According to the findings, the average age for U.S. mothers who had their first baby in 2008 was 25, a year older than the average first-time mother in 1990. Among all women who had a baby in 2008, the average age is 27, up from 26 in 1990. The prime childbearing years remain 20-34 - three-quarters of mothers of newborns are in this age range. Birth rates peak among women in their late 20s.

Since 1990, birth rates have risen for all women ages 30 and older. Although in some cases the number of births is small, the rate increases have been sharpest for women in the oldest age groups - 47 percent for women ages 35-39 and 80 percent for women ages 40-44, for example.

Dual factors

The delay in age of motherhood is associated with delay in age of marriage and with growing educational attainment, the report notes. The more education a woman has, the later she tends to marry and have children. Birth rates also have risen for the most-educated women - those with at least some college education - while staying relatively stable for women with less education. These dual factors have worked together to increase the education levels of mothers of newborns.

Among mothers under age 50 and fathers under age 60, 82 percent say they plan to have no more children. When those parents, as well as parents beyond the childbearing ages, were asked why they decided to limit the number of children they had, the only reason cited as “very important” by most parents (64 percent) was that they wanted to devote time to the children they already had. A total of 76 percent described this reason as very important or somewhat important. A total of 72 percent said the cost of having another child was very or somewhat important to them in deciding to limit their family size.

Cited by smaller groups of respondents as very or somewhat important were the stress of raising children (49 percent), the wishes of their spouse or partner for no more children (46 percent), their age (42 percent) and wanting to have time for other interests (40 percent).

The genders offered different responses about stress, money and the wishes of a spouse or partner, the authors noted. Women (56 percent) were more likely than men (40 percent) to cite the stress of raising children as a very or somewhat important factor in their decision to limit family size. Men and women were about equally likely to say that financial concerns were somewhat to very important; a higher number of women (52 percent) than men (44 percent) said money issues were very important. A spouse or partner’s wishes were cited as very important by 33 percent of men but only 23 percent of women.

Adults who completed high school were more likely than college grads to cite stress and having the time to pursue their own interests as reasons for not having more children. Stress was cited as very important by 35 percent of adults with a high-school education or less and 23 percent of college graduates. Time for their own interests was cited as very important by 25 percent of adults with a high-school education or less and 12 percent of college graduates. Time to pursue their own interests also was cited as a very important reason by a higher share of Americans with household incomes under $30,000 (29 percent) than by those with household incomes of $75,000 or more (13 percent).

Younger parents and unmarried parents were more likely than older or married parents to cite the cost of raising children as a very important reason for limiting their family size. Sixty-eight percent of parents in their 20s and 30s did so, compared with 44 percent of parents ages 40-59 and 43 percent of those ages 60 and older. More than half of unmarried parents (55 percent) cited this reason as very important, compared with 45 percent of married parents.

The New Demography of American Motherhood can be downloaded free of charge at http://pewresearch.org.