Can we decrease breakthrough bleeding in patients with endometriosis on norethindrone acetate?

To compare the breakthrough bleeding in endometriosis patients treated with Lupron-Depot alone, norethindrone acetate following Lupron-Depot, and norethindrone acetate alone.

71 women with symptomatic surgically diagnosed endometriosis were retrospectively evaluated for this study. 28 women were treated with 6 doses of 3.75 mg Lupron-Depot every 4 weeks (Group I). 15 women were treated first with Lupron-Depot 3.75 mg every 4 weeks for 3 to 6 doses, followed by 5 mg norethindrone acetate (Group II). 28 patients were treated for 6 months with 5 mg per day norethindrone acetate alone (Group III). Breakthrough bleeding during treatment was scored mild (some spotting), moderate (lighter than patient's normal menstruation), or severe (as much as patient's normal menstruation or heavier). Multiple comparisons were done by ANOVA (SPSS) among three groups. The age of patients was not significantly different between groups 134.9-36.8 years). BMI of the three groups was significantly different 126.6 +/- 5.8, 27.4 +/- 6.4, 23.6 +/- 4.5, respectively).

Breakthrough bleeding was reported by 14% of Group I, 20% of Group II, and 68% of Group III.

Endometriosis patients who were treated with norethindrone acetate following Lupron-Depot had significantly less breakthrough bleeding than those given norethindrone acetate alone, and the incidence was comparable to Lupron-Depot alone.