1. Vaginal rings delivering progesterone and estradiol may be a new method of hormone replacement therapy 
Takeshi Maruo, M.D., Daniel R Mishell, M.D., Avraham Ben-Chetrit, M.D., Drorith Hochner-Celnikier, M.D., Anna Lissa Hamada, M.D., Harold A Nash, Ph.D. 
Fertility and Sterility 
Volume 78, Issue 5, Pages (November 2002)
DOI: /S (02)

2. Figure 1
Mean serum levels of E2, estrone, and P before and during ring use. The number of subjects contributing samples is indicated for each time point. Values from users of the two ring types are combined for E2 and estrone.
Maruo. Progesterone-estradiol vaginal rings. Fertil Steril 2002.
Fertility and Sterility  , DOI: ( /S (02) )

3. Figure 2
Morphological appearance of the endometrial biopsy specimens obtained before use (A) and after 4-month use of an LP ring (B) in a 57-year-old postmenopausal woman (× 400).
Maruo. Progesterone-estradiol vaginal rings. Fertil Steril 2002.
Fertility and Sterility  , DOI: ( /S (02) )