Babies who are looked after by relatives when their mothers return to work are slow at learning to read, write and speak, according to a report published today.
The study, which was funded by the Government, found that one in seven mothers returned to full-time work within 18 months of the birth of their child. However, babies cared for by relatives were slower at developing basic learning skills compared to those cared for by their parents or a professional childminder.
The report, conducted by researchers from Bristol University, is the largest of its kind to investigate the effects of working mothers on children.
Liz Washbrook, a co-author of the report, said: "Children who were looked after by relatives before they were 18 months old scored significantly lower on reading, mathematics and language tests than those who were cared for by their mother or a paid childminder."
The research, funded by the Department for Education and Skills, involved a team from Bristol University assessing the development of 12,000 children born in 1991 and 1992, at four stages.
It formed part of the on-going "Children of the 90s" project, which has been monitoring the progress of 14,000 children in the Bristol area since 1991. The study found that among the 14 per cent of mothers who returned to full-time work within the first year-and-a-half of giving birth, the children of those who left them with relatives were slower to develop basic learning skills. Between the ages of two and eight, the children were "negatively affected" in terms of reading, writing and speaking, according to the 12-year study.
However, it was children cared for by a friend, relative or neighbour while the mother went to work who suffered "significant ill effects". The report said that boys were affected more than girls.
It concluded: "There are negative effects only for the relatively unusual group of children whose mothers return to full-time work before they are 18 months old.
"It is only those children whose non-parental care consists solely of unpaid care by a friend, relative or neighbour - such as a grandparent - who experience significant detrimental effects.
"Short periods of care by relatives appear not to be damaging: it is sole reliance on relatives to cover full-time working that appears to be less beneficial."
Reassuringly for thousands of working mothers, the study also found that returning to employment after 18 months had no adverse effect on children's development.
However, the findings highlighted the need for policies encouraging flexible and part-time working practices for mothers, as well as inexpensive and high quality child care, according to the authors of the report.
"Relatively few mothers in our study made use of paid care before their children reached the age of two, probably due to the prohibitive costs," said Miss Washbrook and her co-author Paul Gregg.
"The recent increases in financial support for child care may lead to a shift towards paid care by working mothers."
The effects of parents working on the development of their children has been the subject of a spate of recent reports.
Last month, a report by the Joseph Rowntree Foundation, the social policy research charity, found that working mothers struggled to leave their office troubles at work.Reuse content