Hormone replacement therapy (HRT): indications and side effects

Hormone replacement therapy (HRT) has been prescribed to relieve typical oestrogen deficiency symptoms, conserve postmenopausal bone and thereby reduce the risk of osteoporotic fracture, and also to reduce the risk of certain arterial diseases such as ischaemic heart disease (IHD).

Numerous placebo-controlled studies have confirmed that oestrogens reduce the frequency and severity of flushes and sweats, and also improve vaginal dryness. Although not consistent, some data report an improvement in psychological symptoms such as poor memory and concentration. At appropriate daily dose, oestrogens reduce postmenopausal bone loss in both spine and hip; data on fracture efficacy from controlled studies at both of these sites are lacking, but observational data report reductions in fracture risk.

The effects of HRT in women with risk factors for IHD are controversial, with some studies reporting benefits but others not. The majority of the observational data in apparently fit and healthy younger women report an approximate 50% reduction in IHD with use of HRT.

The major long-term concern of use of HRT is risk of breast cancer. There is an approximate threefold excess risk of venous thrombosis with all forms of therapy and an approximate 60% excess risk of gallstones with oral therapy. Other side effects tend to be short-lived and include breast tenderness (due to the oestrogen) and a PMT-like complex (due to the progestogen). Numerous studies report no significant effect on weight, systolic or diastolic blood pressure.