More mothers say the desire to spend more time with their children is stopping them from working longer hours according to a government survey.
The survey looked at the reasons why women did not work 16 hours or more.
Research by the Department for Work and Pensions found that the number of mothers giving this reason had risen by 5% in 2004 from the previous year.
The results came from a sample of 4,471 families conducted in 2004.
The survey, which covered health and education, defined non-working mothers as those employed less than 16 hours.
The report is based on analysis of the Families and Children Study (FACS) which began in 1999.
Initially it covered a representative sample of lone parents and low/moderate-income families, but from 2001 the sample criteria expanded to all couple families with dependent children.
Its findings also include education, health, parental health, benefits and tax credits.
Nearly nine out of ten of those questioned said they had a specific reason for not working 16 hours or more, with "wanting to be with their children" given by 53% of them.
The survey also found there was more use of childcare in 2004 - with 65% of working mothers using some form (up 3% on the previous year).
Some 48% of non-working mothers used childcare, which was up 8% on 2003's figures.
During the period fewer mothers (3% less) reported that there was not enough childcare available.
On the question of health, lone parents were twice as likely to describe their health as "not good" compared with mothers in couple families.
In addition, lone parent families who worked 16 hours or more were less well off than couple families where one parent worked these hours.
The sample was drawn from Child Benefit Records and interviewees were identified as the "mother figure" in the household.