The Pregnancy and Maternity Discrimination Bill, introduced by Labour MP Dan Jarvis, aims to protect new parents and expectant mothers against redundancy.
Previous rules stated employers had to offer a suitable alternative vacancy if offering redundancy to a worker on maternity, shared parental or adoption leave.
The new law extends this protection to pregnant women and new parents returning to work.
More on unpaid carers and pregnant workers:
New mothers' rights in the workplace – everything you need to know
What makes an employee hide a pregnancy from their employer?
New rights for parents and carers are on the horizon in 2022
The UK's business minister Dean Russell said: "Being an expectant or new parent is already a hugely exciting yet anxious time without the added pressure of worrying whether your job is on the line.
"By extending the UK’s world-class workplace protections, today’s reforms will help to remove workplace discrimination and provide improved job security for employees at such an important and precious time in their lives."
Joeli Brearley, CEO of charity Pregnant Then Screwed, said the bill's introduction was a step in the right direction, even if it could have been more impactful.
She said: "Despite our political system imploding, in the past few days, we have seen some small steps of progression when it comes to the rights of women in the workplace.
"We had pushed for this bill to be stronger so that pregnant women could not be made redundant except in exceptional circumstances and we wanted to see the time limit to raise a tribunal claim increased from three months to at least six, but still, a win is a win and we know the passing of this bill will be a huge relief to tens of thousands of women."
Legislation designed to help unpaid carers was also backed by the government on 21 October.
The Carer’s Leave Bill, first introduced by Scottish Liberal Democrat MP Wendy Chamberlain in June 2022, will introduce a new entitlement of one week’s unpaid leave per year for employees who are providing or arranging care.
Workers taking the leave will not need to provide evidence of how the leave is used or who it will be used for, creating a smoother process for both businesses and their employees.
Helen Walker, chief executive at Carers UK, said the new laws would make a big difference to unpaid carers in the workforce.
She said: "We are thrilled that the government has supported the Carer’s Leave Bill at its successful second reading.
"Having worked to support carers in employment for years, Carers UK’s evidence shows carer’s leave would make a significant difference to unpaid carers’ lives, helping them stay in work and improving wellbeing by giving time off to attend appointments, arrange or provide care. As well as supporting families, it also makes business sense, helping retain skilled employees."
