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Updated: Jun 23, 2026
An In Vivo Estrogen Deficiency Mouse Model for Screening Exogenous Estrogen Treatments of Cardiovascular Dysfunction After Menopause
Published on: August 13, 2019
Progestin may modify the effect of low-dose hormone therapy on mammographic breast density
C Panoulis1, I Lambrinoudaki, A Vourtsi
12nd Department of Obstetrics and Gynecology, University of Athens, Aretaieion Hospital, Athens, Greece.
Objectives:
To evaluate the effect on breast density of two low-dose hormone therapy regimens identical in their estrogen component but different in the progestin.
Methods:
A total of 81 non-hysterectomized postmenopausal women were allocated either to 17beta-estradiol 1 mg and norethisterone acetate 0.5 mg (E2/NETA, n = 43) or to 17beta-estradiol 1 mg and drospirenone 2 mg (E2/DRSP, n = 38). Treatment was continuous and lasted 12 months. The main outcomes were the changes in breast density according to the Wolfe classification between baseline and 12-month mammograms.
Results:
Involution of the fibroglandular tissue was not seen in either of the treatment groups. Under E2/NETA, breast density increased in seven women (16.3%). In contrast, only three women (7.9%) exhibited a density increase under E2/DRSP.
Conclusions:
Although hormone therapy appears to suspend breast involution, it does not increase breast density in the majority of treated women. Progestins differing in pharmacological properties may have a variable impact on breast density.
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