As many as 54,000 new mothers a year are being forced out of their jobs by discriminatory employers who treat them differently once they have a baby.
New research by the Equality and Human Rights Commission has revealed that 11% of the women questioned had been dismissed, made redundant or treated so badly they had resigned from a job.
Hannah Martin, from Worthing in West Sussex, has experienced it.
Within months of winning a prestigious advertising award and receiving a bonus, she was suddenly given 24 hours to resign.
She is in no doubt it was because she had started leaving work at 5.30pm on the dot to get back to the baby she was still breastfeeding.
“I was told: You’re s***. You’ve always been s*** and we want you out,” she said.
“They had never said anything negative to me before.”
Ms Martin was stunned and felt she had no option but to leave.
“I had made sure that me being a mum did not impact my work but it was not about my work.
“It was about me being seen to leave when everyone else was still there.”
The research, carried out in partnership with the Department for Business Innovation and Skills, is the largest survey of its kind.
It also found around one in five new mothers experienced harassment or negative comments from their colleagues, employer or manager when pregnant or returning from maternity leave.
And around half of mothers who were allowed to work flexibly said they received fewer opportunities or felt their opinion was less valued than before.
But the project also revealed 84% of employers believe supporting pregnant workers and those on maternity leave is in the interests of their organisations.
Caroline Waters, deputy chair of the Equality and Human Rights Commission, said: “The key finding is that there is a worrying level of discrimination during pregnancy and that can extend through maternity leave.
“That can range from refusal to attend antenatal clinics, right the way through to being made forcibly redundant.”
She said businesses needed help to improve how they dealt with maternity leave and mums returning to work.
Women playing with their children at a park in Norwich have had different experiences with employers.
Laura Black, a community nurse and mother of Connor, said: “I went to a job interview at a local agency and they asked if I was going to become pregnant again so there was some discrimination there.
“It put me on the spot and I didn’t know what to say.”
Justine Mann works in higher education and said family-friendly policies were in place when she had Nathan, aged five, but a friend had suffered discrimination and ended up leaving her job.
And market stall worker Helen Andrews said her employers had done all they could to help when she had 13-month-old Emily.
“They didn’t have any problems with me leaving work for maternity leave and when I came back they were very welcoming,” she said.
The last time a similar survey was carried out in 2005, it estimated 30,000 women a year were being forced out of their job.