Nearly one in five American women in her early 40s is childless, according to a report that shows a striking increase in women who don't have biological children.
The trend was much less common in the 1970s, when one in 10 women did not have children by 40 to 44, the age bracket researchers use to designate the end of childbearing years.
The report, released Friday by the Pew Research Center, cites social and cultural shifts for the change, including less pressure to have children, better contraceptive measures and expanded job opportunities for women.
"I certainly think it's notable that there is such a large increase in the share of women who do not have children for whatever reasons," said D'Vera Cohn, a coauthor of the study. She said that some women were childless by choice; others wanted children but could not have them. A "very, very small number" would go on to have children, she said.
"The fact that nearly one of five women does not have a child of her own -- that's an enormous transformation from the past," Cohn said.
The trend largely held true across races, ethnicities and education levels. One exception was women with advanced degrees -- a master's or higher -- who were more likely to give birth. In 1994, 31 percent were childless in their 40s. In 2008, 24 percent were.
This may reflect a growing belief that women can have both a career and a family, said Tanya Koropeckyj-Cox, a sociologist at the University of Florida.
The Pew report shows that the shift was opposite for women with less than a high school diploma. In 1994, 9 percent of that group was childless. In 2008, that figure was 15 percent -- an increase of 66 percent, says the report, which notes general trends in delaying marriage and childbearing.
Overall, the report found that white women are more likely to be childless, as are women with more education. The analysis, based largely on census data, comes amid changing attitudes about women who do not have children.
In 1988, 39 percent of those interviewed in the General Social Survey said they didn't think people without children "lead empty lives." By 2002, that figure was 59 percent.
Childless women are as happy as women who had children at typical ages, said Amy Pienta, a researcher at the University of Michigan who co-authored a study on the subject. "They are not any more depressed; their psychological well-being is just as high," she said.