Welcome to HCM.
Amenorrhoea may be primary or secondary.
Primary amenorrhoea may be due to uterine agenesis, imperforate hymen, hormonal
disorders involving hypothalamus
, thalamus, pituitary, thyroid, adrenal, ovary and of course not forgetting pregnancy
Similarly secondary amenorrhoea also has a number of causes, including hysterectomy
Wish you all the best.