In a case of secondary amenorrhoea who fails to get withdrawal bleeding after taking estrogen and progesterone, the fault lies at the level of ?

Absence of withdrawal bleeding after Estrogen-Progesterone challenge test indicates that there is local endometrial lesion. Estrogen_Progesterone Challenge test: Indicated as an investigation in case of secondary amenorrhea. Procedure: Ethinyl estradiol 0.02 mg or conjugated equine estrogen 1.25 mg is to be taken daily for 25 days. Medroxyproeterone acetate 10 mg daily is added from day 15-25 Alternately, one course of oral contraceptive pill is given and to observe whether withdrawal bleeding occurs or not Results and interpretation: If there is no bleeding-local endometrial lesion such as uterine synechiae. This is to be confirmed by HSG or hysteroscopy. If withdrawal bleeding occurs- the presence of responsive endometrium but the endogenous estrogen production is inadequate. The defect lies in ovary/hypothalamus/Pituitary Ref: DC Dutta textbook of Obstetrics 8th edition Pgno: 469