In reply to bumpy:
First of all, as a recently-new parent to a soon-to-be one, congratulations, babies are awesome, and being a parent is great.
There has been some interesting advice so far on this thread, but I'm going to sound a note of caution.
As an instructor you're obviously an excellent skier, and I'm sure you will take extreme care and not do anything silly if you ski when you're pregnant. But, you may just catch an edge and fall hard. Or hit a rock off-piste if you are touring. Or hit a hidden icy patch and take a tumble. Or some out-of-control moron might take you out from behind.
So, assuming there is a possibility of you falling, you then have to look at the possibility of that fall damaging your baby. Or, equally as bad, taking a fall and even
thinking that it damaged your baby (when the actual cause might have been something unrelated).
On one hand, the argument goes "is it worth potentially harming your baby just for a a few hours of fun? Surely you can live without skiing for a year or so?".
On the other hand, the counter-argument would say that you shouldn't stop "living your life" just because you are pregnant, and being indoors wrapped in cotton wool is likely to drive you crazy. Doubly so given that, as an instructor, skiing
is your life to a certain extent.
Only you can take the responsibility for that decision. So make sure you think about it well.
The only further thing I would add, as the father of 4 miscarried children, is that the emotional pain of losing an unborn child is considerable. And, according to my wife, the physical pain can be quite unbearable.
I say this now in a happy place and as father of a beautiful 6-month old baby girl. Best of luck and hope the pregnancy goes well.