Nearly four in 10 part-time working mothers would choose to increase their hours if childcare costs were cheaper, research has found.
Some 38% of women in this situation said they would work for longer if childcare was less expensive, according to a survey of 2,000 mothers with children aged under 10 across the UK.
Parents in England are now paying an average of £127 a week for part time childcare, figures show.
In the past year alone, nursery prices have risen by 3% - pushing annual costs to £6,000 per child.
In Inner London – the most expensive region in the UK – the price of a part time nursery place for a child under two is £175 a week, or £9,100 a year, compared to an average £108 a week in Yorkshire and Humberside, or £5,600 a year.
Not-for-profit pension provider the People's Pension, which carried out the research, argued the findings suggest childcare costs are helping to fuel the pensions gender gap as women, who often take on the bulk of caring responsibilities in their family, find it uneconomical to work more hours.
It makes it harder for women to build up a retirement savings pot.
The survey found that after having children, nearly half of women (44%) had reduced their hours, more than a third (36%) left work altogether and more than one in five (15%) returned to work in a lower grade or lower paid role.
Gregg McClymont, director of policy at the People's Pension said: "Of course, many women choose to reduce their working hours or leave their job because they want to spend more time with their kids, but our research is clear - the cost and availability of childcare is a key factor for many women.
"If we're going to tackle pensions inequality, not only are changes to auto-enrolment required but better provision of affordable childcare is a must to enable those mums that want to keep working or work more hours, to be able to."
