Endometrial progesterone and estrogen receptors and bleeding disturbances in depot medroxyprogesterone acetate users

Depot medroxyprogesterone acetate (DMPA) is a very popular hormonal contraceptive. Unpredictable bleeding disturbances are the main reasons for discontinuation and may be mediated through endometrial hormone receptors. This study was aimed to compare the expression of progesterone and estrogen receptors in the endometrium of bleeding DMPA users with that of amenorrhoeic DMPA users.

Subjects were recruited between April 2000 and January 2001. On the day of the third DMPA injection, 42 amenorrhoeic DMPA users and 42 DMPA users who had frequent or prolonged endometrial bleeding and were bleeding on that day were matched by age and body mass index. Endometrial biopsies were collected for immunohistochemical study of progesterone receptor A plus B (PRAB) and B alone (PRB) and estrogen receptor alpha (ERalpha) and beta (ERbeta) expression.

There were 23 adequate endometrial samples from each group. There were no differences in any of a series of comparisons of PRAB, PRB, ERalpha and ERbeta expression in glands or stroma between the groups. Serum estradiol and progesterone levels were also not different between the groups.

Endometrial PRAB, PRB, ERalpha and ERbeta expression in glands and stroma was not different between DMPA users who had frequent or prolonged bleeding and amenorrhoeic DMPA users.