L.D.
Aveda can accomodate, either NW or SE site. They will also let you bring in wine, food, etc. Steam room and mineral soak for those reaceiving spa (not salon) services.
Kalista, a funkier site, will also host parties. It's a fun place ~ in SE/Clinton area.
If you want fancy, Rumi-Simone spa in Lake Oswego is gorgeous and does parties. They have many services for pregnant women. They are more expensive, but really lovely. Steam room and sauna, along with services.
Can you tell that I LOVE spas? :-)