I would consult with the doctor first, but I used to own a Tanning Salon and I was told by my OB that it wasn't the UV rays that were harmful to the fetus, it was the fact that a woman could over heat and/ or become dehydrated, sending her into labor and causing many different issues that I did not want to deal with in my salon nor when I was pregnant myself.
Also, my husband and I went on vacation while I was pregnant with baby #2 and the Dr. said no hot tubs. Pool were ok as long as they were not heated and no baths either. I followed his advise and didn't question it assuming that the heat issue was similar to tanning and I took water aerobic while pregnant that were ok'ed by the Dr. so I swam alot in the pool.
Good Luck!