Does low-dose, transdermal, norethisterone acetate reliably cause endometrial transformation in postmenopausal oestrogen-users?
In a prospective study, the symptomatic, psychological and endometrial effects of a combined oestradiol/progestogen transdermal therapeutic system which delivers a low daily dose of norethisterone acetate have been investigated in 18 postmenopausal women. Treatment was given in 28 day cycles. Patients received transdermal oestradiol 50 micrograms/day continuously and transdermal norethisterone acetate, 0.1-0.15 mg/day, was added for 14 days. Treatment was given for between 5 and 7 cycles. One patient discontinued therapy because of a skin reaction. Low dose, transdermal norethisterone acetate caused few adverse symptomatic or psychological side-effects and appeared well tolerated. Fourteen endometrial samples were obtained during the combined (norethisterone acetate/oestradiol) phase of the 5th, 6th or 7th treatment cycle. None showed hyperplastic or malignant change but proliferative endometrium, indicative of an inadequate progestational stimulus, was observed in 4 biopsy samples. Th
