Depomedroxyprogesterone-induced hypoestrogenism and changes in vaginal flora and epithelium

To identify the effects of depomedroxyprogesterone acetate (DMPA) on vaginal microbial flora and epithelium.

Women who desired DMPA for contraception were evaluated before and at 3 and 6 months after initiation of 150-mg DMPA injections every 3 months. At each visit, we assessed genital symptoms, vaginal signs, vaginal microflora, and histopathology by vaginal biopsies.

Among 38 women observed for 6 months, there was significant reduction in mean serum estradiol level (99.9 +/- 9.3 pg/mL to 26.6 +/- 1.6 pg/mL, P <.001). The number of subjects with any Lactobacillus did not change, but the number with hydrogen peroxide (H(2)O(2))-positive Lactobacillus decreased from 20% before to 12% after 6 months of DMPA (P =.005). The log concentration in colony-forming units per milliliter of vaginal fluid of H(2)O(2)-positive Lactobacillus decreased in a linear manner from 4. 0 +/- 0.6 at baseline to 2.5 +/- 0.6 after 6 months of DMPA use (P =. 006). The mean number of cell layers in the epithelium was reduced slightly from 28.1 +/- 0.7 to 25.9 +/- 0.9 (P =.05), epithelial thickness decreased from 1.02 +/- 0.04 mm to 0.89 +/- 0.05 mm (P =. 005), and the glycogen-positive thickness decreased from 0.81 +/- 0. 04 mm at baseline to 0.66 +/- 0.05 after 6 months of DMPA use (P =. 005).

Depomedroxyprogesterone acetate produced a systemic hypoestrogenic state associated with decreased H(2)O(2)-positive Lactobacillus colonization and slight thinning of the glycogen vaginal epithelial layer. Such changes possibly compromise the vaginal barrier to infection.