Pregnant women and new mothers are suffering increasing levels of unfair treatment at work, including cuts in hours, being put on zero-hours contracts or even forced out of their job, a new report has revealed.
Citizens Advice warned of a growing problem of new and expectant mothers facing discrimination.
The charity said there was a 25% increase in people seeking advice on pregnancy and maternity issues in the past year, with more than 22,000 visits to its website.
Evidence from Citizens Advice included pregnant women and new mothers having their working hours cut, being put on to zero-hours contracts, pressured to return to work early from maternity leave and, in some cases, forced out of their jobs.
One woman turned to Citizens Advice for help when her employer cut her weekly hours by more than half after she told them she was pregnant.
Her boss claimed there was not enough work available to keep her on her previous hours, despite taking on new staff at the same time.
Another woman contacted her employer to find out why she had not received any maternity pay, to be told they had ended her contract while she was on maternity leave.
Citizens Advice chief executive Gillian Guy said: "Pregnant women should be supported at work, not made to fear for their livelihood.
"It is concerning that more and more new and expectant mums are experiencing discrimination issues at work.
"People with a baby on the way will have a lot on their minds already. The last thing they need is a threat to their income or job security. All employers should respect and uphold the rights of staff who are new parents or expecting a baby."
A Government spokesman said: "Discrimination is unlawful and completely unacceptable. Attracting and retaining female talent is crucial to economic growth and, as well as being against the law, it does not make business sense for employers to alienate and discriminate against women in their workforce.
"We are determined to stand up for all workers and are taking action to tackle discrimination at work against pregnant women and parents."