NEW YORK -- More women are staying at home full-time to raise their children, according to a new Pew Research Center report released Tuesday.

Factors cited by Pew to explain the increase include more immigrant mothers, who tend to stay home with children in greater numbers than U.S.-born moms; more women unable to find work; and ambivalence about the impact of working mothers on young children.

The share of mothers who do not work outside the home rose to 29 per cent in 2012, the study found.

That's up from a low of 23 per cent at the turn of the century, according to the report. At the height of the recession in 2008, Pew estimated 26 per cent of mothers were home with children.

The 29 per cent includes women who are married, single, disabled, enrolled in school or unable to find work.

The largest share of at-home mothers -- roughly two-thirds of 10.4 million -- had working husbands. A growing share -- six per cent in 2012, up from one per cent in 2000 -- said they could not find a job, according to Pew, which relied on U.S. Census and other government data.

No matter what their marital status, mothers at home are younger and less educated than working counterparts, the report said. Most married moms said they were home specifically to care for the kids, while single mothers were more likely to say they couldn't find a job, were ill or disabled or were in school.

Among all at-home mothers in 2012, 51 per cent had at least one child 5 or younger, compared with 41 per cent of working mothers.

The researchers said one of the most striking demographic differences between at-home mothers and working mothers is their economic well-being, with about 34 per cent of at-home mothers living in poverty, compared with 12 per cent of working mothers.

Relatively few married at-home mothers with working husbands qualify as "affluent," at nearly 370,000 with at least a master's degree and a median family income of over $75,000 a year in 2012. That number amounts to five per cent of married at-home mothers with working husbands.

The "elite" marrieds stand out from other at-home mothers as disproportionately white or Asian. About 69 per cent are white and 19 per cent are Asian. Only seven per cent are Hispanic and three per cent are black.

Mothers more likely to stay home are among demographic groups on the rise in the U.S. For example, 40 per cent of immigrant mothers were at home with their children, compared with about a quarter of mothers born in this country.

Among at-home mothers living in poverty in 2012, 36 per cent were immigrants, the report said.

The report points to stagnant incomes for all but the college-educated as a possible factor for less-educated workers in particular who might be weighing the cost of child care against wages and deciding it makes more economic sense to stay home.

While clearly attitudes over the decades toward working mothers have improved, "most Americans continue to believe that it's best for children to have a parent at home," said D'Vera Cohn, a senior writer at Pew who worked on the report.

Since 2008, about 70 per cent said when questioned in an ongoing social survey that a working mother is just as capable as an at-home mother of establishing the same "warm and secure" relationship with her children. But 60 per cent of Americans in a recent Pew survey said children are better off when a parent stays home to "focus on the family," compared with 35 per cent who said children are "just as well off with working parents."