You have to sponsor your wife for PR before she can get citizenship. She will need medicals and a chest x-ray. The chest x-ray can be done with an apron or you can defer it until the baby is born. She can not get her PR without having done the medicals first.
If you move back to Canada now, some provinces will not even consider giving your wife health care until she already has her PR + she has spent at least 90 days in their province after she got her PR so you will not get child birth covered in these provinces. Forget going to Ontario or BC.
One of the most liberal provinces when it comes to covering people is AB so if you move to AB, as a returning Canadian from overseas, you would get AB health first day and it is possible that they would cover your wife as well. When you enter Canada, you should ask for a visitor record for her based on that you want to sponsor her for PR. To AB, she might be seen as your dependent and as she has a visitor record which may allow her to stay in Canada for a year, she may fall under their definition of person who lives in AB for more than 6 months a year and may be eligible even if you have not applied to sponsor her yet. However, you should discuss this with AB health first to make sure before you move. If you must sponsor her to get coverage, you can sponsor inland without having done the medicals first. They will ask for them later. If you sponsor outland, you must include the medicals when you apply.
You will find AB health care here: http://www.health.alberta.ca/health-care-insurance-plan.html
