Hi. I would do the hardest thing possible right now - wait and see. If INZ feel that they cannot issue the visa(s) because of medicals they will send you a letter to that effect giving you the chance to respond. This is when you throw all the extra specialist letters, evidence of the forthcoming happy event etc at it. If it still looks doubtful, you could ask for a standard Visitor or Limited Visa for 6 months or so. It would get you through the immediate situation and give you time to prepare for the next application. Even with the possibility of a medical waiver though, the person still has to be considered a low risk of costing the health Services in NZ too much money.