Endometrial histology and circulating levels of medroxyprogesterone acetate (MPA), estradiol, FSH and LH in women with MPA induced amenorrhoea compared with women with secondary amenorrhoea.

Circulating levels of medroxyprogesterone acetate (MPA), estradiol, progesterone and gonadotropins were determined in 11 women on long-term treatment with depot-MPA (Depo-Provera DMPA) 150 mg i.m. every 12th week as a contraceptive. The women had amenorrhoea due to the treatment. Endometrial biopsy was performed one week after injection and at the end of the 12 week period. Blood samples were taken on the same occasions. The findings were compared with those in 12 untreated women having secondary amenorrhoea. MPA was still detectable in serum and the end of the 12 week period. Endometrial biopsies showed gestagenic effects in the second as well as in the first biopsy. No MPA was detectable in the untreated women with amenorrhoea, and no gestagenic effects could be demonstrated in their biopsies. The estradiol levels in the DMPA group were in the range of the early follicular phase of a normal menstrual cycle and showed a significant rise at the end of the 12 week period. On the last sampling occasion the estradiol levels did not differ from those in the untreated women with secondary amenorrhoea. The levels of progesterone and gonadotropins were in the range of the early follicular phase in both groups. These observations support that DMPA 150 mg i.m. every 12th week is a depotpreparation with prolonged effect, and inhibits ovulation and produces endometrial changes by means of biologically active serum concentrations throughout the 12 week period.