Haemophilia

I worked with a lady in Christchurch had at least one kiddie with haemophilia. She left our 'company' to work full time with the Haemophilia Foundation of NZ (HFNZ). Belinda is an incredibly cool, approachable sort, so I am guessing that the rest of the organisation would be the same. You should get in touch (http://www.haemophilia.org.nz/index.html) HFNZ with them.
I have very limited personal knowledge about the disorder, however I would have thought that if your boy was positive, that there would be enough time to transfer him to hospital comfortably after the birth for treatment if needed. In any case, have a talk to the northern rep at HFNZ - they'll have much better advice.
Best of luck and warm thoughts!