Eli5: Why do our menstrual cycles last so long?

Question

EDIT: I probably should have said why does *menstruation* last so long

I know every women is different and this doesn’t apply to everyone, but many women experience 2 heavy days, 1 medium day and then 2 extremely light days. How come our bodies can’t rid it all in 3 days instead of dragging it out into 5 with 2 almost pointless days?

In: Biology

Answer 1

I think it is because the uterine lining doesn’t build or breakdown all at once.

I imagine the shedding of endometrium less like wiping off a table, more like peeling wallpaper-there’s layers to deal with.

Before my hysterectomy, I had an 84 day period. So as much as I hate being the it could be worse lady, it definetely could be worse.