RESUMO
Bleeding disturbance is the major reason for discontinuation among depot medroxyprogesterone acetate (DMPA) users. However, the causes of progestin-induced bleeding are not well understood. The aim of the study was to examine the correlation between the occurrence of uterine bleeding and progesterone receptor (PR) levels in the endometrium. Forty-five matched pairs of age and body mass index in DMPA users with bleeding and amenorrhea were studied. The endometrial PR levels were evaluated. The PR score was assessed semi-quantitatively. Forty-two subject pairs met the criteria. There was no difference in serum estradiol and progesterone levels between the groups. No correlation between the number of bleeding days and PR score nor between the number of bleeding days and serum estradiol and progesterone level was detected. The stromal PR score in DMPA subjects with amenorrhea was significantly higher than those with bleeding (p < 0.05). By contrast, the PR score in glandular endometrium was not significantly different between the groups (p > 0.05). In conclusion, after a second dose of DMPA, subjects with amenorrhea had a higher stromal PR score than those with uterine bleeding.