Objective: To identify the effects of depomedroxyprogesterone acetate (DMPA
) on vaginal microbial flora and epithelium.
Methods: Women who desired DMPA for contraception were evaluated before and
at 3 and 6 months after initiation of 150-mg DMPA injections every 3 month
s. At each visit, we assessed genital symptoms, vaginal signs, vaginal micr
oflora, and histopathology by vaginal biopsies.
Results: Among 38 women observed for 6 months, there was significant reduct
ion 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 (H2O2)-positive Lactobacillus decreas
ed from 20% before to 12% after 6 months of DMPA (P = .005). The log concen
tration in colony-forming units per milliliter of vaginal fluid of H2O2-pos
itive Lactobacillus decreased in a linear manner from 4.0 +/- 0.6 at baseli
ne 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 decreas
ed from 0.81 +/- 0.04 mm at baseline to 0.66 +/- 0.05 after 6 months of DMP
A use (P = .005).
Conclusion: Depomedroxyprogesterone acetate produced a systemic hypoestroge
nic state associated with decreased H2O2-positive Lactobacillus colonizatio
n and slight thinning of the glycogen vaginal epithelial layer. Such change
s possibly compromise the vaginal barrier to infection. (Obstet Gynecol 200
0;96:431-9. (C) 2000 by The American College of Obstetricians and Gynecolog
ists.).