Bruce Wayne
he doesn't know because Y/n will find it awkward to say it in front of him. but he understands when he sees her crawled up in a ball or her mood changes a lot he will cuddle with her.
Dick Grayson
he will give her hot chocolate and kisses her forehead then hugs her
Jason Todd
he doesn't even knows what periods means and he won't really care. but he will try his best not to anger Y/N.
Tim Drake
cuddles,chocolate,ice cream,blankets and hugs all the time.
Damian Wayne
he isn't disgusted but he will try to Make Y/N comfortable all the time and will kiss her cheek and tell her that he loves her