Objective: To compare profiles and related factors of irregular bleeding induced by different types of low-dose hormone therapy (HT) and a Chinese formulated herbs products.
Methods: Applied with open-labeled, randomized, and clinical trial design, 136 postmenopausal women were assigned into four groups: group A: estradiol valerate (E2 V) 1 mg/d + medroxyprogesterone acetate (MPA) 2 mg/d; group B: conjugated equine estrogen 0.45 mg/d + MPA 2 mg/d; group C: tibolone 1.25 mg/d; group D: a Chinese formulated herbs product (Kuntai) 4# tid. Each subject took element calcium 400 mg/d and vitamin D 200 IU/d concomitantly. Modified Kupperman scores were assessed on baseline and every 3 months thereafter and irregular bleeding was recorded on menopausal diary every day. The duration of this study was 1 year. Results The efficacies were similar in three HT-managed groups, but was better than in group D, although the latter was also effective in alleviating menopausal symptoms. Hazard ratio (HR) of irregular bleeding was 1.00 in group C, 2.43 in group A (95% CI: 1.08-5.46), 3.12 in group B (95% CI: 1.42-6.88), and 0.73 in group D (95% CI: 0.26-2.04). Most cases initially experienced bleeding in the first 3 months but such initiation was a bit later in group C. Endometrium, as detected by B-mode ultrasound, increased approximately 1 mm in HT groups, while it was a bit thicker in group C. Long periods in reproductive age and short time since menopause were high risk factors for irregular bleeding.
Conclusion: Profiles of irregular bleeding in 3 commonly used types of low-dose HT are different and some factors such as long period in reproductive age and short time since menopause may contribute to bleeding initiation.