Tens of thousands of new mothers every year are being fired or forced to quit their jobs due to workplace discrimination, a new study has found.
One in ten women surveyed by the Equality and Human Rights Commission (EHRC) had been sacked, made redundant or treated so badly they had to leave in the months after returning from maternity leave.
Meanwhile, a fifth had experienced harassment or negative comments from colleagues or managers either while pregnant or once they had given birth.
Even when allowed to work flexible hours, around half said they were offered fewer opportunities to progress.
Researchers said the findings suggest some 54,000 new mothers are being edged out of their jobs each year.
The study, carried out in conjunction with the government's Business Department, interviewed more than 3,200 women on their experiences in the workplace as a new parent.
Other findings include:
10% said they were treated worse by their employer upon returning to work
7% said they were put under pressure to hand in their notice
5% were given a pay cut or a lower bonus
Deputy chairman of the EHRC, Caroline Waters, said the research highlighted the "worrying" degree of prejudice women still face in the workplace.
The commission is now leading a campaign to raise awareness of the problem, and will produce a 'toolkit' to help employers better manage pregnant staff members.
As part of the study, thousands of employers were also surveyed.
Researchers found most managers declared they were firm supporters of female staff both during and after their pregnancies, with four out five agreeing that new mothers were just as committed to their work as their colleagues.
But a third of employers refused to disagree that pregnancy puts an "unreasonable burden" on the workplace.
General secretary of the TUC union, Frances O'Grady, accused companies of being "in denial" over the scale of anti-pregnancy discrimination.
She also called on the government to waive the current £1,200 fee women face if they want to pursue a pregnancy discrimination claim.
A government spokesman vowed that the findings of the study would be used to inform future policies.