<prompt> Most common cause of pubey menorrhagia:AnovulationMalignancyEndometriosisBleeding disorder  <response>: Causes of Abnormal Uterine Bleeding Pregnancy Anovulation Coagulopathies Exogenous Hormones Infections Systemic or Endocrine Problems Anatomic Causes Investigations: Pregnancy testing, regardless of sexual activity Hb : Anaemia PLT : Thrombocytopenia PT APTT : Coagulopathies VWD : Ristocetin cofactor activity antigen, factor VIII; blood grouping and typing Thyroid functions Serum progesterone : day 22-24; 3ngml LFT RFT : Suspected cases 95 abnormal uterine bleeding is due to AUB in adolescents It is due to immaturity of Hypothalamic-Pituitary-Ovarian axis leading to anovulatory cycles Reference: TEXTBOOK OF GYNAECOLOGY; SHEILA BALAKRISHNAN; 2nd edition; Page no: 51 