My office frequently has a very strong sewer odor. Somedays are worse than others. They are supposed to be getting it fixed, by worry is that it could potentially be harmful to my baby. I'm seven months along, and haven't had any complications thus far, and if I need to make a change to my working environment, I will.

I was a HR director for years and I would advise you to tell your immediate superior that the smell makes you uneasy and worried and that you may need to take a sick day. You should not be forced to work in this environment. A plumber will not take long to find the source and repair it. Your company needs to get moving.