To evgreen: why is Leung being shortsighted? Surely it's the fault of the CURRENT administration to allow this situation to spin out of control, and an entire medical tourism industry to ensue, leading to arguably misguided health infrastructure to be established (at the expense of the local requirement). As i said earlier, there is probably enough capacity for the local market.
In a way though Jt06 is right..banning pregnant altogether will likely lead to ongoing 'hide outs'. The real issue is how to address the right of abode in law.