A one-year multicenter study of efficacy and safety of a continuous, low-dose, estradiol-releasing vaginal ring (Estring) in postmenopausal women with symptoms and signs of urogenital aging.

Objective: We studied the efficacy, safety, and acceptability of an estradiol-releasing (6.5 to 9.5 micrograms per 24 hours) silicone vaginal ring (Estring) in postmenopausal women with symptoms and signs of urogenital aging during a treatment period of 1 year.

Study Design: The study was open with blind analysis of vaginal cytologic testing. In addition to gynecologic examination, subjective symptoms were assessed and vaginal pH and urinary samples (for bacteriuria) were obtained before insertion of Estring. This procedure was repeated every 3 months up to 1 year's treatment, together with requests concerning acceptability and adverse experiences. At inclusion and end of Estring treatment, vaginal smears for evaluation of cytologic results were obtained.

Results: Estring induced a high maturation value in the vaginal mucosa and restored vaginal pH to levels normality seen in fertile women (< 5.5). For most variables a 90% responder rate (proportion of cured and improved patients) was found after 3 months and up to 1 year regarding subjective symptoms and objective signs of vaginal mucosal atrophy. Twenty-eight (20%) of 136 women, withdrew from the study, 8 (6%) of them because of adverse events. Three women reported vaginal bleeding, none associated with malignancy or endometrial proliferation. Ten (7%) reported vaginal irritation, and in two cases vaginal ulcers were found. About 90% did not remove the ring during any of the 3-month treatment periods, and 78% used the four consecutive rings continuously up to 1 year. The ring was given a strong preference (p < 0.001) by patients with previous experience of other administration forms.

Conclusion: Estring represents a safe, highly effective, and very well-accepted administration form for long-term treatment of urogenital disorders caused by estrogen deficiency in postmenopausal women.