Giving women a lengthy period of maternity leave could harm their career prospects, according to a new study.

The study from the Research Institute of Industrial Economics in Stockholm, Sweden, shows that the more family-friendly a country tries to be, the less its women succeed in the workplace.

New mothers who have a year or more off before returning to work often hit a ‘maternal wall’, the authors of the study said.

Employers assume they are not committed to their jobs and deny them the opportunities given to the childless.

The study revealed that women in Anglo-Saxon countries where maternal leave is less generous climb higher up the career ladder than in Scandinavian nations where years of female-friendly legislation may have inadvertently disadvantaged women.

If there is too much job protection for mums-to-be then firms avoid hiring women, who instead find jobs in the public sector, the authors of the study said.

“When you have high levels of maternity leave, it pays for women to be in the labour market but not aim at a high-flying career. They are derailed from their objectives. The more generous you are, the fewer women you are likely to see at the very top,” Times Online quoted Magnus Henrekson, the head of the research institute and one of the authors of the study, as saying.