I remember during an EK roadshow somebody asked about a pregnant wife, and they were told that if you get hired and come to Dubai, your wife's medical would not cover "pre-existing conditions" and that pregnancy was a pre-existing condition. So stay in the US, get your kid born there, and then come to Dubai. Seemed a bit weird that a pregnancy/baby delivery would not be covered under a new insurance program.
Only if she was pregnent at the time of joining.
After a qualifying period (six months I think) pregnency and delivery are covered under the company scheme.