Tulip Siddiq, an opposition Labour MP for the London constituency of Hampstead and Kilburn, postponed the date of her cesarean section by two days, her office confirmed to CNN. Siddiq's husband, Christian Percy, will push her through the House of Commons lobby in a wheelchair, her office said.
After developing gestational diabetes, Siddiq was advised by medical professionals to deliver the baby either on Monday or Tuesday. She asked if she could move the date back to Thursday, and her doctors then agreed, her office said.
Parliament has a longstanding arrangement that allows British lawmakers who are absent from parliament to be "paired" with opposing MPs who agree not to vote, thereby balancing out the tally.
The Speaker of the House of Commons, John Bercow, told Parliament on Monday that Siddiq should be allowed to have a proxy vote, but did not have the power to grant it. Bercow said that the notion that Siddiq should have to be wheeled in to vote was "completely uncivilized" and "regrettable."
"I believe that it is absolutely essential, not just in terms of the rights of the honorable member [Tulip Siddiq], but for the reputation of this House as an institution approaching, or starting to take an interest in, the modern world, that she should be facilitated to tomorrow to vote," Bercow said, calling on the leader of the Commons, Andrea Leadsom, to act urgently on the matter.
Siddiq's office confirmed on Tuesday that no offer of a proxy vote had been extended. "Given the enormity of the vote, anything other than a proxy vote wouldn't be acceptable to us," a spokesperson told CNN.
According to the Evening Standard, Siddiq spent the weekend under observation in hospital after having steroid injections required to be taken before birth. Physicians wanted her to have the injections 48 hours before the operation, but that would have meant she would still be in hospital during the vote.
"The Royal Free (Hospital) has been very clear on their legal and health duties. This is a high risk pregnancy and I am doing this against doctor's advice," she told the paper.
CNN's Eliza Mackintosh contributed to this report.