<unk>  is a diagnosis of exclusion. Girls who<unk>  at a young age may have primary<unk> . The differential diagnosis are androgen excess, pituitary tumors (rare), tumors of the third ventricle (rare) or other conditions leading to chronic malnutrition. Diet history and bone density investigations should also be done to determine if female athlete triad is present.
Exercise amenorrhoea
Puberty menorrhagia
Lactational amenorrhea
Premenstrual water retention
Functional hypothalamic amenorrhea
Polycystic ovary syndrome
Endometritis
Premenstrual syndrome