New research from the ESRI has found mothers with higher childcare costs when their child was aged three tended to then work fewer hours when their child was five.
The study was based on 'Growing Up in Ireland' data which tracked the employment of mothers across the first five years of their child's life.
Research professor with the ESRI Helen Russell says many parents face significant childcare costs, especially in urban areas, and that the mothers working life can suffer as a result.
"We found that on average families were spending 12% of their disposable household income on care for their three-year-old and this rose to 16% for lone parents and 20% for low-income households," she said.
Ireland South MEP Deirdre Clune said more needs to be done to support female employees who have children.
"In order for women to succeed in the workplace - they need to be supported," she said.
"That support can come from a number of places such as the State, employers, managers, family and friends.
"The Government is working hard to ensure it supports working parents and I would also urge employers to do what they can too to support parents.
"At European level there is a lot of work going on to help women in the workplace. Much of the work I am engaged in at the European Parliament is on the promotion of a good work/life balance.
"Employers can have a big influence in the success of female employees and even small changes can mean a lot."