Anatomical

Congenital causes include:

• intersex states - usually the effect of an underlying endocrine order such as congenital adrenal hyperplasia; for example, true hermaphroditism, and male or female pseudohermaphroditism
• malformation of the female genital tract - such as uterine agenesis, vaginal atresia, imperforate hymen. Müllerian agenesis is responsible for about 10% of primary amenorrhoea cases (1)

Acquired causes include:

• endometrial fibrosis - Asherman's syndrome, tuberculosis; both rare in the UK
• cervical stenosis - usually due to surgery, especially cautery or conization

Reference:

• (1) Practice Committee of the American Society for Reproductive Medicine (2008) Current evaluation of amenorrhea. Fertil Steril 90(5 Suppl), S219-S225.