Hello, I don't take hrt, but I did take it briefly and from what I understood, the estrogen that one takes, builds up the lining of the womb and then the progesterone causes that lining to shed. ( a bleed )
Perhaps you're on a low dose or maybe some hrt works differently. Mine did build up lining in womb and caused a fibroid to grow, but I was on the gel?!
I'm sure someone who knows more about it will be along soon. All the best.. x