elle, HK is not what you would call advanced in terms of women's right/maternity leave, work/life balance ect. I have never been asked the pregnancy issue, how many children do I plan to have, am I pregnant now, asked to take a urine sample for unspecified reasons except in HK. It is illegal here to discriminate against an actually pregnant woman but not necessarily before she gets pregnant. Sadly Hk is not Australia, the UK or the US when it comes down to this issue.
In terms of what Gracey says, I'm not sure. I wouldn't ask a helper during the interview process what was asked of me (see above) because I found it pretty rude and rather offensive, but I think once the helper starts to work for you then a chat about letting you know in advance if she does become pregnant so that the household disruption would be minimised would be okay. Personally pregnancy and maternity leave, is what it is, a bit of an incovenience but not the end of the world, and if you like your helper (as I do), I do hope one day she does have her own family as it's what she hopes for and its something I've enjoyed greatly.