The Labour MP for Hampstead & Kilburn developed gestational diabetes during her pregnancy leading to her Caesarean being brought forward to this week.
She was expected to give birth today or tomorrow after having steroid injections over the weekend to help accelerate the development of her baby’s lungs.
But, it has now been postponed until Thursday after doctors approved the delay.
The 36-year-old told : “If my son enters the world even one day later than the doctors advised, but it’s a world with a better chance of a strong relationship between Britain and Europe, then that’s worth fighting for.”
Her office confirmed to ITV News that her plan is to be taken through the Commons lobby in a wheelchair by her husband tomorrow evening in order to vote.
Ms Siddiq represents a constituency home to 20,000 European nationals and is determined to give them a voice in Parliament.
In an event where an MP is too ill or unavoidably absent, they are usually paired with an opposition MP who also cannot vote so the outcome is not affected.
"I’m choosing in a sense between career and my family life and I feel it’s totally unfair and if we want more women in politics and we want people to come from different backgrounds, we need change and to introduce proxy voting", Ms Siddiq told .
"I’ve sat down with my husband Chris and he said to me this is my choice but that he would support me.
"I am thinking about my child’s future when I made this decision - his future in the world. If it comes to an absolute emergency, I will of course prioritise the baby’s health."
The Commons Speaker said Ms Siddiq should be allowed to vote on the Brexit deal from hospital rather than having to be wheeled into Parliament.
John Bercow said it was "completely uncivilised" to make Ms Siddiq postpone giving birth to her child to have her say on May's Withdrawal Agreement.
He added he would like to see the procedure known as "nodding through", where an MP who is on the parliamentary estate but unable to physically cast their ballot has their vote counted anyway, extended further so Ms Siddiq can have her say from her hospital bed.
He said he "would be happy on my part on my own shoulders to agree to that", but added: "Personally I think it preferable that she should have a proxy vote, but that does seem to me to depend on cross-party agreement."