An objective and subjective assessment of uterine blood loss in postmenopausal women on hormone replacement therapy

OBJECTIVE: To determine the volume of withdrawal blood loss in women taking hormone replacement therapy (HRT). DESIGN: Prospective randomized double blind cross-over trial. SUBJECTS: Twenty-nine postmenopausal women, with climacteric symptoms. INTERVENTIONS: The women were treated with cycles of 2 mg oestradiol valerate for 21 days combined with either 250 micrograms levonorgestrel or 10 mg medroxyprogesterone acetate, for the last ten days. Each woman was randomly allocated to one of the preparations and switched to the other after four months. MAIN OUTCOME MEASURES: Uterine blood loss was estimated by the alkaline haematin method. Bleeding patterns were recorded specifying the number of days with bleeding and subjective rating of the amount of blood lost. RESULTS AND CONCLUSIONS: The mean uterine blood loss was 35.2 ml and was equivalent to the normal menstrual blood loss. There was no significant difference between therapies but the women themselves considered that they bled more heavily when taking the levonorgestrel combination. The intraindividual variation in blood loss was small, independent of preparation taken, but the variation between individuals was large. Withdrawal bleeding started 2-3 days earlier when the women used the medroxyprogesterone acetate compared to the levonorgestrel formulation.