How can I find other pregnant/new moms in my area?

I don't know anyone else who is currently pregnant or a new mom, but I'd love to find a group of women who I could connect with and maybe meet up with for baby things. I signed up for a birthing class, hoping to meet some people, but my husband and I are the only signed up for this session!
If you're in a "mom group", where did you meet the other moms?