A 17-year-old girl has had her menstrual period once and hasn't had it since. What could be the reason?

Patient's question:

Irregular menstruation, doctor recommended it is an endocrine problem

Doctor's answer:

First, you need to know if your last menstrual period was your first period or a normal period. Did anything happen before this situation occurred? For example, significant emotional distress, stress, or a change in location, etc. If necessary, check your hormone levels.