When is it safe to start having unprotected sex after starting trinessa? I started taking trinessa eight days ago. I missed my third pill at the correct time but I remembered it 12 hours later and took it. Is it safe for me to have unprotected sex without

If . If the pill you missed was on day 3 (through 21) and you took it as soon as you remembered (12 hours later) then you do not need to use a back-up method of birth control. I've attached a website with great information about the pill and what to do if you miss any at particular times of the month. It's really helpful!