Dear islandbabe,
There is some kind of misunderstanding involved. Welcometocanada is worried regarding the health and safety point of view that Doctors normally advise not to travel after 7 months of pregnancy but you are answering with regards to legal point of view that it is legal for a pregnant woman to land in Canada on PR visa even she is 9 months pregnant.
I understand that if pregnancy is quite mature then physician may not go for X-ray which will be postponed till baby is delivered. Therefore, no one will get PR visa before the birth of the baby and hence no case of travelling and landing to Canada involved during pregnancy period. But if somehow medical is completed, then it will also be possible to travel, I believe, in that case, Welcometocanada must plan to travel and land in Canada immediately after getting the PR visa.