The study found a third of women had experienced sexual harassment in the workplace.
PR professionals in 37 countries took part in the first GWPR Annual Index, which found a majority (64 per cent) believe having more women in the boardroom would improve profitability and 81 per cent said more should be done to help women get there.
Eight in ten survey respondents believe the biggest barrier to career progression was childcare and caring responsibilities.
More than a third (35 per cent) believe being a carer had negatively impacted their career, with 42 per cent of women saying they alone take on most of the caring responsibility in the home.
Four in ten respondents believe women with children are promoted more slowly, and 24 per cent of parents said their company offered no paid parental leave.
To address the boardroom imbalance, the majority (70 per cent) of survey respondents would like more flexible working arrangements, with 47 per cent saying they want to be able to work remotely and 40 per cent wanting flexible start and finish times.
A fifth of women (20 per cent) felt that flexible working was perceived negatively by their company.
WE founder and global CEO Melissa Waggener Zorkin described the survey findings as "unacceptable".
"We simply cannot wait for the industry to catch up," she said. "Instead, we must identify where we can make the most immediate impact. And ensure each employee can play a role in shaping a better path forward.
"It’s our job as leaders to make sure that happens. For me, this means ensuring gender equity at the leadership level and across the company."
The study also looked at sexual harassment in the workplace. A third of the women surveyed had experienced this, 60 per cent of those women did not report it to their employer and more than a third (35 per cent) said their company had no policies or training in place to deal with sexual harassment in the workplace.
These results are similar to an earlier PRWeek and Women in PR study into sexual harassment in the workplace.