A prospective randomized controlled study comparing two doses of gestodene in cyclic combined HRT preparations on endometrial physiology.

Postmenopausal women taking oestradiol 17-beta 2 mg daily were randomized to receive either 25 or 50 microg gestodene from day 17 to 28 of the cycle in a double-blind study. Placental protein P14 (PP14) and CA 125 concentrations in uterine flushing, endometrial morphology and irregular bleeding after 12 cycles of study were observed. Eleven and 12 women in the 25 and 50 microg groups respectively completed the study. There were no significant differences in pre-treatment biochemical and morphological indices between the groups. The median PP14 concentration increased from 332 to 5800 ng/ml (P < 0.001) and from 145 to 27 160 ng/ml (P < 0.001) in the 25 and 50 microg gestodene groups respectively. No between-group significant rise of PP14 was observed. Similarly, no significant change was seen between the initial and post-treatment concentrations of CA 125 for either group. All biopsies were atrophic at inception of the study, and both regimens produced secretory endometrial transformation in the majority of biopsies. No between-group difference was observed in the morphometric indices measured, or any significant correlation between the concentrations of PP14 or CA 125 and morphology. The mean number of days of withdrawal bleeding (3.8 and 4.2 days for 25 and 50 microg respectively) were similar. In conclusion, both regimens produced a significant rise in uterine flushing concentrations of PP14, but not CA 125. PP14 is a sensitive biochemical marker in the assessment of endometrial response to hormone replacement therapy.