Endometrial response to concurrent treatment with vaginal progesterone and transdermal estradiol

ABSTRACT Objective To describe the effect of the intermittent administration of vaginal progesterone and a low-dose estradiol patch on endometrial stability, as assessed by the rate of amenorrhea and endometrial stimulation. Methods This was an open study in which 64 moderately symptomatic, postmenopausal women were treated in the outpatient clinic of our University Hospital for different intervals up to 1 year. The treatment consisted of a combination of patches delivering 25 µg/day estradiol and intravaginal pills containing 100 mg of micronized progesterone. Patches and pills were administered concomitantly in a twice-a-week protocol. The endometrial response was assessed by endovaginal ultrasound completed with suction biopsy when required. Results Both cumulative amenorrhea and no-bleeding rates increased progressively and reached 88.9% and 100.0%, respectively, by the 12th month. Isolated or repetitive episodes of bleeding, bleeding and spotting, or only spotting were reported by three, four, and 12 women, respectively. Endometrial thickness remained unaltered. Endometrium was atrophic in the seven women in whom a biopsy was performed. Conclusion The substantially reduced progestogen load determined by this combination achieved an acceptable incidence of spotting or bleeding when associated with a low estrogenic dose. There was no apparent endometrial stimulation. Additional studies are required to confirm this observation.