How can I cause a miscarriage?

I knocked some chick up from a one night stand, and she wants to have the baby. I think she's operating under the misguided notion that if she keeps it, I'll stay with her. Not the case, she's ugly and kinda fat (I was drunk) so I'd like if she'd get rid of it. But she won't. So I was thinking about getting in good with her again and trying to cause a miscarriage. How can I do it?