This open-label, non-comparative study was conducted at a single center to evaluate the effects on the endometrium of a 24-day regimen of a combined oral contraceptive containing gestodene (GTD) 60 microg and ethinylestradiol (EE) 15 microg.
Healthy parous women who were > or = 18 years old and had had regular menstrual cycles for the prior 3 months were randomly assigned to one of two groups. Subjects in group A underwent endometrial biopsies during the late luteal phase of the pretreatment cycle and between days 15 and 24 of cycle 6. Subjects in group B had biopsies between days 15 and 24 of cycle 3 and during the late luteal phase of the post-treatment cycle. GTD 60 microg/EE 15 microg was taken for the first 24 days of a 28-day cycle, followed by placebo pills for 4 days, for a total of six cycles.
Data from 27 women were included in the analyses. Eleven of the 13 evaluable baseline biopsies were classified as secretory. Three of nine subjects with evaluable biopsies at cycle 3 and four of nine subjects with evaluable biopsies at cycle 6 had an atrophic endometrium. Post-treatment biopsies showed a typical secretory endometrium in seven of 11 subjects with evaluable biopsies.
The results of this study show that the 24-day regimen of GTD 60 microg/EE 15 microg produced effective endometrial suppression.