One in seven women are made redundant after maternity leave amid growing levels of discrimination, a new study has found.
One in 10 women surveyed said they were replaced by their maternity leave cover while one in seven were overlooked for a promotion.
More than half of women subjected to discrimination "suffered in silence", some in fear that it would damage their career, according to the survey of 1,000 women carried out by law firm Slater & Gordon.
Campaign group Maternity Action said the number of new mothers seeking advice over discrimination had doubled every year for the last three years since the economic downturn.
Rosalind Bragg, director of Maternity Action, said: "In 2005 research found 30,000 women each year lost their job as a result of unlawful pregnancy discrimination.
"We have raised the issue with the Government but we are unable to get any action.
"It's critically important that this issue becomes a government priority to enable women to remain in the work force if that's what they would like to do."
The head of the charity added: "Pregnancy discrimination is largely invisible. This is partly because many matters are solved by agreements which prevent women discussing the case publicly.
"A bigger problem is that many women are unaware of their rights or do not have the money to take action.
A spokeswoman for Slater & Gordon said the statistics were "sad and shocking".
She added: "It is against the law to be sacked or treated unfairly because you are pregnant, or taking maternity leave.
"More than half of the women polled suffered in silence because they were either unsure of their rights, they didn't know where to turn for help or they thought seeking help would damage their future career prospects."