How to tell my new boyfriend I had an abortion in the past?

I haven’t been dating this new guy very long, only about a week, but I’m wondering when would be a good time to bring up I had an abortion recently (almost 3 months ago) before I ever met him and I don’t talk to the person I conceived with anymore. I don’t know how he would take it. He seems pretty open minded but I kind of just want to get it over with before it goes any farther because I don’t want to be with someone who I have to hide that from. Need suggestions how to go about it, thanks :)