In a regularly cycling human female, which can be the root cause of menstrual failure?

In a regularly cycling human female, which can be the root cause of menstrual failure?
In a regularly cycling human female, which can be the root cause of menstrual failure?
In a regularly cycling human female, which can be the root cause of menstrual failure?
In a regularly cycling human female, which can be the root cause of menstrual failure?

failure?