What are the causes of amenorrhea?

Causes of Amenorrhea: 

A. Ovarian causes/failure: 

• Ovarian dysgenesis ( due to Turner's syndrome)
• Premature ovarian failure 
• Steroid biosynthesis defect 
• Resistant ovary syndrome 
• Oophorectomy, chemotherapy, radiotherapy 
• PCOS 
• Mumps oophoritis 
• Drugs: Depot medroxyprogesterone acetate

B. Gonadotrophin failure (Hypothalamic-pituitary disease ):

• Pituitary causes:
• Kallmann syndrome/ nIHH ( normosmic idiopathic hypogonadotropic hypogonadism)
• Sheehan syndrome 
• Hyperprolactinaemia 
• Prolactinoma 
• Idiopathic hyperprolactinaemia 
• Hypothyroidism 
• Physiological in lactation 
• Dopamine antagonist drugs
• Possible hypothalamic causes-
• Hypothalamic amenorrhea 
• Weight-related amenorrhea 
• Exercise-induced amenorrhea and anorexia 
• Post-pill amenorrhea 
• General or chronic illness ( e.g. chronic renal failure)
• Excessive stress

C. Androgen excess: 

• Gonadal or adrenal tumours (e.g. Arrhenoblastoma, Androgen-secreting adrenal tumour )
• Congenital adrenal hyperplasia 

D. Uterine or vaginal cause/abnormalities:

• Pregnancy 
• Asherman's syndrome 
• Absent uterus 
• Imperforate hymen 
• LNG-IUS ( levonorgestrel-releasing intrauterine system)

[This image is taken from Kumar & Clark’s Clinical Medicine 9e, Box: 26.32]

From Taber's Cyclopedic Medical Dictionary:

Arrhenoblastoma: An ovarian tumour that secretes male sex hormone, causing virilization in the female 

Asherman's syndrome: Presence of adhesions in the endometrial lining of the uterus, often causing secondary amenorrhea, infertility, or repeated spontaneous abortion.

Post-pill amenorrhea: Amenorrhea after stopping contraceptive therapy. 

Sheehan syndrome: Hypopituitarism due to an infarct of the pituitary after postpartum shock or hemorrhage. 

Kallmann syndrome: A disorder whose hallmarks are the congenital absence of the sense of smell and decreased the functional activity of the sex organs, resulting from insufficient production of gonadotropin-releasing hormone.

[Source: Kumar & Clark’s Clinical Medicine 9e and  Essentials of Obstetrics and Gynaecology, page: 27]