Hi Lilly. My wife gave birth to our first son at Royal Columbian Hospital in New Westminster in 2009. She had only a TRP and an inland application in process. Royal Columbian required payment at the same time as admittance (before you are allowed to go upstairs and start pushing!). They wanted $6000. If I remember correctly, this would cover doctors, nurses, one day stay at the hospital, and even an emergency C-section should it come to that. It did come to that for us. Our son was born at 5 am and my wife begged the doctor to discharge her that evening, despite having had no time at all to begin healing to her incision. The reason: an extra $1500/ night.
This is why my wife is in Mexico right now, having just delivered our second child. We had to sacrifice our inland application (which should have been accepted 7 months ago) in favor of not being completely wiped out by medical bills again. We decided to have our second child based on CIC's application timelines (BAD idea).
I was just speaking with someone at work this evening about medical coverage for non-residents. He seemed confident that you could buy private insurance that would cover you. I am skeptical, though I suggest you look into it yourself before allowing my doubts to dissuade you.