The survey consulted 1,000 women, 500 of whom have taken maternity leave and a further 500 who plan to do so.
It reveals 78% feel asking about maternity benefits in a job interview would jeopardise their chances of landing the role.
It also reveals 42% of female employees would only ask about maternity benefits at the point of announcing a pregnancy. Almost half (41%) generally feel uncomfortable about discussing maternity benefits.
The problem is exacerbated as only around one-third (32%) of women say they were given any information about maternity benefits when they started their role. Additionally, 39% report that this information is difficult to find. For 13% of employees there is no published information on maternity benefits in their workplace so they have no choice but to ask.
Glassdoor career and workplace expert Jon Ingham calls keeping maternity benefits "under lock and key" short-sighted.
"In fact, a more honest and open attitude towards maternity benefits could improve the quality of candidates looking to work at your organisation," he said.
"It may not be an intentional decision for employers to keep this information from female employees, however forcing them to ask for it is clearly causing a great deal of distress for many women. Transparency around benefits in the workplace can actually build greater trust.”