I had blighted ovum, gone for medical abortion, was unsuccessful, had d&c on 1st march 2014, got 1st cycle on 1st april, when should i start ttc again?

Don't wait!! : I'm not sure why you waited for your first cycle after your d and c . After a successful d;c if you don't want to be pregnant you should start your pills that week. Your risk of ovulating is high. You can start birth control pills anytime in the cycle. Just use back up, like condoms, for the first seven days. If you have had unprotected sex in the last 10 days, you may want to wait to make sure that you're not pregnant again.