When my wife got pregnant during our application process, I emailed the visa office (Manila). Here is their email reply:
Dear Applicant,
In view of the information you provided, please submit the following documents after your spouse has given birth to your child or once the documents are available:
- updated forms for yourself (IMM0008 and IMM5406)
- completed forms for your spouse (IMM0008DEP, IMM5669 SCHEDULE A, and IMM5406)
- Photocopy of the passport bio-data page of your additional dependent
- 3 passport-size photos of your additional dependent (45mmx35mm white background)
- NSO birth certificate of your additional dependent (my country's "official" original birth certificate document)
- Processing fee for your additional dependent, if he/she is accompanying you to Canada ($150, Bank Draft)
- Updated IMM008 SCHEDULE 3 and proof of funds (~$17k+ for family of 3, Bank Certification)