I actually had one done a few weeks ago. I was 34 weeks at the time (37 now) and it was amazing!!! Just make sure the massage therapist is prenatal certified. I had one when I was pregnant with my son (now 9yrs old) and the massage table actually had a piece that was removed so that my belly hung while I was In heaven lol this last one had a regular bed and I was on my side while she worked on me then switched sides when it was time. It was still so nice! Def worth it :)
It is totally fine as long as they are familuar with pre natal massaging. Its such a relaxing and wonderful thing to do when your pregnant. Especially if they have the pre natal tables for your belly so you can lay on your belly.
if it is a trained person doing the massage i'd say it is totally safe