Possible congratulations

Theoretically a child does not equate to a genuine relationship (many people have children together and are not in relationships with one another).. but as long as it is not the only proof you have submitted, it can strengthen your case... Mentioning a pregnancy on an application can't really hurt (hopefully medicals are done already, certain aspects (X-rays) cannot be done on pregnant women and can cause delays until after the birth..
If you do not get thru before the baby is born, CIC will want the baby's info (birth papers on file, and you will need the Childs citizenship and/or travel papers - best to get that moving as quickly as possible when he/she is born)... If you are a PR yourself, you will need to add the child to your wife's application
If you are a canadian citizen by birth or immigration, your child will have a right to citizenship if born outside of Canada ... If you are a citizen through birthright (born outside of Canada to Canadian parent(s)), your child born outside of Canada would not be a citizen at birth and need be added to the application...
Until your wife has rights to Canada, the child has no rights until after he/she is born... Sorry...
Hope that helps
Chelle