how long does breakthrough bleeding last on hrt?
The incidence of breakthrough bleeding is high in the first 3-6 months of continuous combined HRT and progestogen-only contraceptive use and may remain marked for up to 1 year (MacLennan et al., 1993; Udoff et al, 1995). Bleeding during the normal menstrual cycle occurs from spiral arteri- oles (Markee, 1940).