When you apply for the health card, it required you not leave the province within 6 months. If you went back to China within this 6 month, when you come back, you will find the card has been cancelled. When you re=apply for it, it will be very complicated. You should keep all your proof of when you left the country and when you come back in case they want to see it. There is no stamp on passport for you entering or leaving Canada. So, sometimes, nothing will satisfy those officers in Ministry of health but the air ticket. If you are coming back for baby delivery, you'd back earlier to have this sort out first. I tell you. NOT EASY!