well, I was in the same condition as almost all my pregnancy period was passed with me being in a visitor status, and by the time our baby was delivered the OHIP coverage hadn't started yet... all the period we used midwives to look after my pregnancy that cost nothing except some blood work tests (about $40 each). the delivery was free too, as it was done with a help of midwives, we just paid hospital fees that was around $400.
but if one decides to use obstetrician's help the final cost can be up to $5000 together with hospital fees.