UK to bring in maternity leave for ministers
The bill was drawn up because the government's top legal officer, Attorney General Suella Braverman, is due to have a baby shortly.
She is believed to be the most senior woman in the Cabinet to give birth.
But under existing rules, she would have to resign or hand her responsibilities over to be split between several others, The Times daily wrote.
A Downing Street spokesman said the "current rules are clearly outdated and need fixing".
The new legislation will enable women to take six months' leave while being paid their ministerial salary.
On Thursday, the bill was to have a first reading without debate in the House of Commons.
"There weren't any rules at all," she wrote in the Guardian daily in 2018, saying she had to make ad hoc arrangements, experiencing "insecurity and dependence on other people’s goodwill".
Proxy voting was brought in after Labour MP Tulip Siddiq had to delay a Caesarian section in 2019 and arrived in a wheelchair to take part in a Brexit vote.
Labour MP Stella Creasy in 2019 became the first MP to hire a locum to work on her behalf in her constituency.