In Slates Dear Prudence column, she gives advice to a woman who had asked an eight months pregnant woman to meet her at a bar -- the pregnant woman thought that was insensitive, even though her friend made clear that she was expected to only order soft drinks. Prudence said she could understand why an 8 months pregnant woman would not want to try to perch on a narrow bar stool.
I comment because this answer leaves out 2 more important and likely reasons she might not want to go to a bar. The first in most jurisdictions would be 2nd hand smoke. But even more uncomfortable is the high likelihood that just being in a bar while that visibly pregnant would generate a long loud lecture on fetal alcohol syndrome from a stranger. For some reason, the normal social constraints are not felt regarding the conduct of pregnant women -- their seems to be some societal proprietary interest in fetuses that over rules it. I think this must have something to do with the choice vs. right to life debate, but I am not sure what.