I was a figure skating instructor when I was pregnant with my first child, I was on the ice teaching the whole time, and stopped 5 days before I gave birth. My doc was nervous but since I had been a competitive skater for 12 yrs and knew what I was doing they said I was ok. I did stop my own skating, as I was practicing 6 days a week, as a precaution. I haf a less chance of falling teaching than I did actually working on my skills. If you know how to, and can do it well, I don't feel its an issue, however if you are a beginner or only do it a few times a year, I think you shouldn't. Ask your doc to be 100%.
Im 26 weeks and plan on teaching my son how to skate this winter. obviously i won't do it the way i did last year where i wore skates too.
Yes its fine!!! Just remember your pregnant not a porcelain doll do as you want obviously without causing purposeful harm to yourself or baby... havefun :D