This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of menstruation, Subject name: Gynaecology & Obstetrics
All are true about Abnormal uterine bleeding except : 
Select and explain. 
A. Blood loss of less than 50 ml, B. Cycle duration is more than 35 days or less than 21 days, C. Bleeding period lasting 7 days or more, D. Irregular bleeding during a regular cycle
A: Blood loss of less than 50 ml
Answer: A: Blood loss of less than 50 ml 
Explanation: Normal Menstrual Loss The upper limit of blood loss in a normal menstruation is considered as 80ml. Any bleeding above the specified normal limit is termed as abnormal uterine bleeding. Normal Menustration: Cycle interval-28days(21-35 days) Menustral flow- 4 to 5 days Menustral blood loss-35ml (20- 80ml) Common causes of AUB: 1.DUB 2.Infections 3.Endocrine Dysfunction 4.Pregnancy Complications 5.Hematological disorders 6.Neoplastic growth. Reference: Textbook of Gynaecology; Sheila balakrishnan; 2nd edition; Page 48 DC Dutta's Textbook of Gynecology; 7th edition ,page 152