I asked another geek (Fifi La Fume) about pregnancy massage as she is very experienced in it. The following is the reply that she sent me, I'm sure she won't mind me putting it here, it's such good information!
"I have my clients lay on their side in the recovery position, I place a bolster under their bent top leg to support it and make sure they are level (i.e their arm and hips are level to leg), the bottom leg is straight I also give them a pillow to hug and if they are in the 3rd trimester a small folded towel under their bump. I use a double flannel sheet (which is already on the bed so they can slip under it after they're undressed). I also make sure their shoulder is of the pillow at the top of the bed so their head is supported correctly and if they aren't laying with their back straight then I ask them to move ever so slightly - i makes side lying massage easier if their back is straight.
I did a massage course with Well Mother, it was ok, but it was more about pregnancy than an actual routine. They also showed you how to massage on the floor, but this was really difficult unless you're about 5ft 1, being 5ft 7 it wasn't easy. I use my massage couch.
I would also suggest you buy some pregnancy massage dvds which give great ideas and explain how to drape and how to have the client on the bed.
Depending on what they need i work more on that area. If I'm just doing the back, then I keep the back covered and start on the neck, shoulder and arm, roll down the sheet and effleurage the back standing at the top of the bed and take it from there. After about 15/20 minutes I get them to turn over to do the other side of their back. It takes a while to get into the swing of doing a side lying massage, but the clients love it.
With this massage it's trail and error, what works for one lady won't work for another - as I'm sure you already know.
My basic routine is scalp, neck, shoulder, arm, back, abdomen, top leg, foot, bottom calf, foot, turn over repeat. Also do leg and arm stretches when needed."
Hth's. I have to say, though, that on the odd occasion when I massage a pregnant lady, they seem to prefer to sit on a chair and rest on the couch. I suppose it depends whether you're doing just a back massage or more than that.