Returning to work on a part-time or casual basis presents almost as much a barrier to breastfeeding for new mothers as working full-time, further fuelling the push for a national paid maternity leave scheme.
A study of almost 3700 mothers and their babies six months after the babies were born found that the rate of breastfeeding was lower for women who had returned to work part-time as well as those who had returned full-time.
Six months after giving birth, 56 per cent of women who were not working were breastfeeding. This dropped to 44 per cent for women who returned to work part-time and 39 per cent for women working full-time.
The research, led by Melbourne University, with La Trobe University and the Murdoch Children's Research Institute, is based on a 2004 longitudinal study of Australian children and will be published in May in the journal Acta Paediatrica.
The lead author, Amanda Cooklin, a researcher at Melbourne University's Key Centre for Women's Health in Society, said a lack of paid maternity leave and workplace support was interfering with many women's capacity to breastfeed. Other issues included a lack of privacy, fatigue, inflexible work schedules and un-supportive employers.
The World Health Organisation recommends exclusively breastfeeding babies for six months. But this was not possible for many women.
"It's clear from our findings that in Australia, working reduced hours every week doesn't contribute to a mother's ability to continue breastfeeding," Ms Cooklin said. "This is further support for the current call for paid maternity leave, because the lack of paid maternity leave means women resume work earlier than they would like to."
The Productivity Commission, which is conducting an inquiry into parental leave, released an issues paper this month which noted that returning to work is an important factor in mothers stopping, or not starting, breastfeeding.
It said deferring work could have a positive impact on increasing the duration of breastfeeding, which would be good for a baby's health.
The Sex Discrimination Commissioner, Elizabeth Broderick, said even an initial period of 14 weeks' paid leave would be a good start to get breastfeeding established. She said in a time where there were skills shortages, businesses would be smart to encourage women to return to work by providing facilities to enable breastfeeding.
"We need to recognise that breastfeeding is an important part of child health and development, and if we are serious about being inclusive of women, then we need workplaces which are breastfeeding friendly," she said.
The president of the Australian Breastfeeding Association, Margaret Grove, said where companies made it easier for women to breastfeed, it was a win for both parties. "The employers get happier women returning earlier to work and the women feel supported in the workplace," she said.