I usually have slightly different headcanons for each elf but I feel like this is one that applies to every Tolkien elf.
They absolutely freak out every time their human partner is on their periods. Elf women do get periods but they’re not as often, heavy or painful.
Even if your periods aren’t that painful or heavy, the slightest mention of fatigue, blood, cramp or nausea and they are carrying you back to bed. Good luck doing absolutely anything because they won’t let you.
“I can make my own cup of tea.”
“Nope. Too sweet and delicate, must protect you.”
Carries you to bed and returns like 5 minutes later with every blanket, heat pack, tea and sweet they can find.
It’s so stressful for them but they mean well 😅