Maria Miller, Minister for Women and Equalities, said she is "determined" to tackle the workplace discrimination of pregnant women and new mothers.
The EHRC's new inquiry into the issue is costing a £1 million and follows more than 9,000 pregnancy discrimination claims brought against UK employers since 2007, The Independent reported.
– Maria Miller, Minister for Women and Equalities
It’s unacceptable. I am determined that we tackle these systemic problems which leave women feeling undervalued and penalised.
We have made... significant changes to help women at work but there is more to do.
A maternity equality charity said unlawful treatment of new mother is "widespread" in the workplace.
Rosalind Bragg, director of charity Maternity Action, called for "urgent action".
– Rosalind Bragg, director of charity Maternity Action
The principles of non-discrimination were established decades ago and should be accepted as an essential part of the business environment.
Since the economic downturn began, pregnant women and new mothers have faced an increasingly difficult time in the workplace. Unfair and unlawful treatment of new mothers is widespread and action is urgently needed.
Pregnancy discrimination imposes major costs on new families at a time when they are least able to handle additional financial stress.
Pregnant women can experience prejudice while they're on maternity leave, or on their return to work, according to anecdotal evidence gathered by the EHRC.
Launching a new research project, EHRC head Mark Hammond vowed to uncover the extent of the problem.
– Mark Hammond, head of the Equality and Human Rights Commission
It is very concerning that in 2013 a number of women are still being disadvantaged in the workplace just because they are pregnant.
That would be unlawful discrimination and needs to be tackled.
We will look at existing research, gather new evidence and carry out our expert analysis to establish the extent of the problem and advise on how best it can to be addressed.
A review to examine pregnancy and maternity discrimination in the workplace has been launched by the Equality and Human Rights Commission (EHRC), which said bias against pregnant women or those returning to work after maternity leave "needs to be tackled".
EHRC head Mark Hammond said it is "very concerning" that women in modern society are discriminated against at work because they choose to have children.
Experts will investigate employers' practices towards workers who are pregnant or on maternity leave, and these employees' experiences.