Employers must do more to help reduce the stress levels of working mothers, a report suggests.
Striking a balance between work and family life can be difficult
Under new rules introduced in April, parents of children under six have the right to ask their employers for flexible working practices.
Recent figures indicate that almost six in 10 mothers with children under five are in some form of employment.
But a study for the Joseph Rowntree Foundation indicates that "family friendly" employment policies are often of limited help if working mothers feel overloaded and under stress while at work.
A team of researchers at South Bank University in London questioned 37 mothers and 30 fathers in couples with at least one pre-school child.
Eligibility to request flexible working
A worker must have worked for the employer continuously for at least 26 weeks at the date the application is made
Applications must be made no later than two weeks before the child's sixth birthday, or 18th birthday in the case of a disabled child.
All of the mothers involved were working either part-time or full-time in a hospital or an accountancy firm.
The researchers found the women wanted to work - not only to increase the family income, but also because they felt their employment was having a positive impact on family relationships.
But some expressed concerns that their jobs had a negative impact on their families - particularly when they were overstretched at work, felt tired, or had trouble "switching off" after a bad day in the workplace.
Some of the fathers questioned also expressed concerns about the demands placed on their partners at work, and the effect that work-related stress could have on their children and their relationship with their partners.
The report, published on Friday, says that most employers' "family friendly" policies focus on the hours parents spend at work, rather than the quality of that time.
More attention could be paid to controlling workloads, managing the intensity of work, and ensuring goals and targets were achievable in the time available to employees.
Dr Tracey Reynolds, a research fellow and co-author of the report, said: "Stresses in family relationships can arise as much from the quality of time spent at work by mothers as the amount of time they spend at work.
"Family friendly workplaces policies and practices may have helped some of the mothers we interviewed to modify their time schedules, but they were ineffective in helping them to deal with the stresses of paid work and the strains that they placed on family relationships."
Workplace cultures also needed to change so that working mothers felt confident in requesting flexible working practices without feeling it would inhibit their career development.
Dr Reynolds added that the issue of stress at work applied to all employees - not just working mothers - and that employers needed to be more creative in helping their staff achieve an effective work-life balance.