An online survey of 2080 mothers has revealed that only four-in-ten mums thought their bosses understood how to handle pregnant staff - and only half said they thought they were aware of their own rights and responsibilities.
The survey also revealed that 30,000 British women every year lose their jobs just for having a child.
Other figures were that almost 45 per cent of women suffer some form of discrimination at work when they become pregnant, 14 per cent suffer financially, and seven per cent are sacked, made redundant, or treated so badly they feel they have to leave.
The survey carried out by the Equal Opportunities Commission (EOC) and parenting website Netmums, concluded that the results of the survey tallied with the findings of their two-year investigation into pregnancy discrimination. This had found that many businesses did not know how to handle pregnant staff.
The investigation also found that smaller businesses were the worst because they had little experience of dealing with pregnant workers, as they only encountered an average of one pregnancy every ten years. It was also seen that companies with less than ten staff were the hardest hit financially ,when a worker became pregnant.
In response, the EOC has produced a toolkit for employers containing practical advice on how to manage pregnant women and new parents, which was designed with the help of small businesses across the country.
This comes parallel to the government's new 'Pregnancy and work' leaflet, which includes a tear-off section for employers, reminding them of their responsibilities and the guidance available to them. This will be given to women with babies due on or after April 1.
The new regulations also mean that paid maternity leave has been extended to nine months, while unpaid maternity leave has been extended to one year. Mothers can now go into work for up to ten 'keeping in touch' days without losing their maternity pay.
At the same time, the EOC is also calling on the government to provide HR advice and more financial support to small businesses with a pregnant employee.
Says Jenny Watson, Chair of the EOC: "Women are now nearly half the workforce. There's no turning back from this major social change, so it's vital that workplaces are equipped to make pregnancy at work a good experience.
"If we fail to tackle the knowledge gap surrounding the rights of pregnant women and new parents at work we run the risk of seeing these women drop out of the workforce altogether.
"Those who have been unfairly treated whilst pregnant suffer financially and emotionally and are far less likely to return to their jobs. As well as damaging families, this costs employers millions in recruitment and training and causes significant damage to Britain's economic productivity."
As a result of the EOC's investigation, all pregnant women are now given a statement of their rights and responsibilities early on in their pregnancy.
Jenny Watson was quoted adding: "Welcome though these changes are, small and micro employers still need further support to manage pregnancy at work if they are to enjoy the benefits of retaining pregnant staff."
Director of Netmums Sally Russell says: "This survey backs up the existence of these problems that we see mums discussing on Netmums every day. Netmums welcomes the work of the EOC in highlighting this issue and in providing this excellent toolkit for employers.
"Mums make great employees and there is a lot of evidence that employers who are sympathetic to the needs of new parents are rewarded.
"It is sad that so many businesses are short-sighted and risk losing loyal, hard-working, responsible staff by making life difficult for pregnant women or new mums returning to work."