Sarah, curious of the context, I searched your previous thread. I think you nailed it with your comment:
What I do find interesting is that nobody encourages people to give up on a PhD if they find out they're pregnant but if you're contemplating it and deliberately planning it it is seen as a big no no.
In your other thread, you were asking if would be hard to have a baby and do a PhD at the same time. The unequivocal answer to that is, Yes, it is. (Personally, I disagree with many answers there about it being better to wait - careers tend to 'start' at the PhD, and people won't really pay attention to a period of leave before the degree, but when your academic publishing record has a giant gap due to mat leave... well, I'm still trying to dig my way back out of that. Anyway, you said you were going back to industry anyway, so that's likely not even relevant.)
But here you're asking about planning to have a baby and how to go about it. I suspect the 'judge level of support' thing was meant to be more a chat around the topic and try to figure out if you're going to find yourself in a supportive environment or not, before you decide to TTC, not given you've decided, to let someone know! You could still do that, it might help figure out who to approach first -- e.g., what faculty member has had a long string of pregnant, successful PhD students (there was one at my PhD institute - everyone knew it would work out fine in his lab) and perhaps get vague pointers. But I wouldn't do it in the context of a decision made, or even looking fact-finding. More general interest, if you can manage it.