M..
I was on lexapro when I found out I was pregnant and quit it cold turkey and didnt really have any side effects. I was pretty bitchy, but I chalked that up to quitting smoking cold turkey too.
I was about 6 weeks when I found out I was pregnant. I think the sooner you stop the better. My baby didnt have any birth defects. Im pretty sure its long term use while pregnant that can cause problems. But, like I said, sooner the better.