Let me share my experience here with you all. In case the baby was delivered after submitting your application, they will send a request letter in your account. This will be about pending xray for your wife and new born baby's birth certificate along with medicals. These will be based on the EDD for your wife.This means you would have submitted all the relevant documents when you first got your ITA and a request letter stating that your wife is pregnant and she is expected to deliver so and so date. Once they send you the request you for the above mentioned documents they will add another column in your submitted application in your account with upload docs option.Once you collect all your documents you will upload all of them there.
It took them 6months to update my account with additional documents request.
I first submitted my application on Aug-8th 2018.First time i got any reply from them was on dec13th,2018.
They sent a Request letter in my CIC account and asked to submit all the docs by 7th March 'cos my Wife's EDD was march5th.
So they gave me exactly a month to submit New born's Birth cerificate,Wife's Xray, and baby's medicals,Passport scans.
Along with these you will have to submit Imm000 and imm5406 with all the details again.
Imm0008 they asked me to submit the copy with Original signature of the principal applicant.
After all this i am waiting to hear from them.
All the best.