Hi wrcaston.......I had to read that post twice as it is a mirror image of our situation!
EOI in May 1st, we are expecting third child in October too!
Here is info provided by our agent: (I told them before EOI and before I filled out State nomination)
This won’t have an impact on the visa process until you have been assigned a case officer, which won’t be until after we have lodged your final visa application. The problem arises when asked to do the medicals, as this involves a chest x-ray which can be harmful to an unborn baby. Therefore, once you have been assigned a case officer we will inform them that Lynn is pregnant. The case officer may ask that you all hold off on the medicals and police checks until the baby is born, at which time the baby will be added to the application and you will all do the medicals at the same time or it could be the case that the case officer asks you all to do the police checks and medicals as normal but allows Lynn to bypass the chest x ray until the baby has been born.
Hope this helps!
PM me if you want any other info as we appear to be on the same timeline