Blessed with children as well as a career outside the home, working mums may seem to have it all.
But actually they suffer a double guilt burden - that they are bad mothers because they work and bad employees because they have a family, a study shows.
Researchers found that working mothers agonised more about their job outside the office than fathers and had more negative thoughts about their family while at work.
The researchers studied 'mental labour' in middle class parents with pressurised jobs. They define the term as thoughts and concerns that impair performance, make it hard to concentrate and harm our sleep.
The study focused on 402 American mothers and 291 fathers in dual-earner families who kept an emotions diary.
Mothers were found to worry for five hours a week more than men and spend more time being anxious about work when they were with family. Men seemed more able to switch off from work more easily.