The survey of 2,000 women from a range of business sectors, half with children and half without, suggests two-thirds (67%) are worried about the impact having children would have on their career.
Of the women who don't have children, almost one-half (49%) feel their current career doesn't offer them the flexibility they would need to care for a family.
Among those with children, 24% have changed their career after becoming a parent, while 65% said they would consider retraining as a way to gain further flexibility in the workplace.
Balancing childcare and work commitments is cited as the main barrier to staying in employment for new mothers, with one-fifth saying a lack of support from their employer has made it difficult.
AAT career coach Aimee Bateman called the findings "sad but not surprising".
"In my work I have come across a lot of women who worry about balancing their care and career commitments or who have decided to retrain as their current role provides little flexibility," she said.
"This is a shame as working mums are brilliant employees who can often get more done in less time. The quality of work people produce is important, not the number of hours that they sit at their desks.”
