I had sciatica, but I think it was caused more from a previous car accident, then worsened by pregnancy.
During the car accident, one of my hips were pushed more forward than the other. When the sciatica came, it was almost unbearable!
I could absolutely not sit or lay on the floor at all or I wouldn't be able to get up because the pain was so bad.
As Ingi stated, I DID go to a chiropractor. It helped so much. They tried to manipulate my hip back into place but she said the bigger the baby becomes, the more pain I would experience (not only does the uterus push on the sciatic nerve, but the baby will also).
There's not much you can do about it besides going to the chiropractor. Plus, you get a massage afterwards!