Congratulations, I pray a safe delivery for you.I haven't handled this yet as I'm still pregnant and registering an EOI in Ontario but I've seen posts that there's a letter/form during processing wherein we can add the baby as dependent and explain the circumstances when we receive ITA.
Here are the links. Hope this helps and let us know what happens to your application
https://www.canadavisa.com/canada-immigration-discussion-board/threads/baby-was-born-after-ita.520638/
https://www.canadavisa.com/canada-immigration-discussion-board/threads/child-born-after-receiving-canada-pr-ita.557051/
Thanks for the links and got this other one below via the ones you sent.
https://www.canadavisa.com/canada-immigration-discussion-board/threads/dealing-with-post-ita-pregnancy.529951/