Secretory endometrial protein PP14 in serum from post-menopausal women receiving continuous combined oestradiol-cyproterone acetate: correlation with serum hormone concentrations and bleeding patterns

The secretory endometrial protein PP14 was measured in serum from 49 healthy, early post-menopausal women receiving continuous combined oestradiol valerate/cyproterone acetate (2 mg E2V + 1 mg CPA daily) or placebo over a period of 2 years. In the hormone group, serum PP14 increased from 2.1 micrograms/l to a maximum of 8.1 micrograms/l after 1 month of treatment, then fell after 3 months to 3.8 micrograms/l and remained at that level for the rest of the 2-year period. After the first month, the occurrence of uterine bleeding was associated with significantly increased serum PP14 levels. Bleeding was not correlated with the serum concentration of 17 beta-oestradiol (E2) or CPA, or the CPA/E2 ratio. Serum PP14 was significantly dependent on the serum concentration of E2, but not on that of CPA. The present data confirm that serum PP14 levels reflect the secretory phase of the endometrium and that bleeding during continuous combined hormone replacement therapy is probably caused by a sub-optimal hormonal balance.