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Southern Cross Medical Library

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Hormone replacement therapy (HRT)

Hormone replacement therapy (HRT) is the use of medications containing female hormones to replace hormones the body no longer makes naturally after menopause.  Its purpose is to treat hot flushes and other symptoms of menopause, most commonly in cases of early menopause (before the age of 45) or when menopausal symptoms are severe.
Due to risks associated with HRT the New Zealand Ministry of Health recommends use of HRT in the lowest possible dose for the shortest possible time, and no longer recommends the use of HRT for the prevention of heart disease or stroke, or as a first line treatment for osteoporosis.

General information

During menopause, oestrogen and progesterone production is reduced. Menopausal symptoms, such as hot flushes, sweats, and vaginal dryness, can occur as the body adjusts to these hormonal changes. The risk of developing osteoporosis (bone thinning) also increases during menopause.
The duration of menopausal symptoms varies considerably between women. On average, symptoms last for around two years. Approximately 20% of women pass through the menopause without noticing any symptoms, whereas approximately 15% of women report severe symptoms. 

HRT delivery methods and regimens

Hormone replacement therapy can be taken in the following ways: 

  • Tablets taken by mouth
  • Skin patches
  • Vaginal creams or pessaries
  • Implants under the skin.
Not all delivery methods will be appropriate for all women. This should be discussed with the doctor or specialist who is prescribing the therapy.  Different regimens of HRT work in different ways and produce different effects. Some regimens mimic the menstrual cycle, so that monthly bleeding occurs.  Continuous combined oestrogen and progesterone leads to an absence of periods in most women.  
Women who have had a hysterectomy are likely to be prescribed oestrogen alone. Women who have a uterus are more likely to be prescribed a regimen that includes progesterone. This is to protect against cancer of the endometrium (the lining of the uterus).

Before prescribing HRT the doctor will take a full medical history. The doctor should be advised if the woman has a history of any of the following conditions as HRT may not be appropriate in these circumstances: 

HRT may also not be appropriate for women who have severe varicose veins, are obese or who smoke.

HRT benefits and risks / side effects

When considering hormone replacement therapy it is important to discuss the potential benefits and risks of the treatment with a doctor.  The risks may vary depending on whether oestrogen is given alone or in combination with progesterone, and depending on the woman's current age and age at menopause.  The dose and type of oestrogen, other health factors such as risk of cardiovascular disease or cancer, and family medical history will also contribute to the assessment of risk in an individual person's particular circumstances.

A patient and her doctor may conclude that the potential beneftis of HRT may outweigh the risks. Benefits of HRT include: 

Disadvantages of HRT include irregular bleeding with some hormone regimens and side effects such as breast tenderness, headaches, bloating or weight gain.  Health risks associated with HRT may include: 

  • Increased risk of breast cancer (8 extra cases per 10,000 population per year)
  • Increased risk of heart attack (7 extra per 10,000 per year)
  • Increased risk of blood clots, which can dislodge and travel to the lungs (causing pulmonary embolism) or brain (causing stroke)
  • Increased risk of ovarian cancer (with oestrogen-only therapy)
  • A slightly increased risk of gallstones
  • A slightly increased risk of endometrial cancer
The New Zealand Ministry of Health recommends that if HRT is prescribed, it should be used in the lowest possible dose for the shortest possible time (no more than 3-4 years). It further recommends that the need for continuing HRT treatment is reviewed with the doctor every six months.

Further information

For further advice about menopause and HRT contact your GP or Practice Nurse.


Capital and Coast DHB (2013) Hormone replacement therapy. (Pamphlet) Capital and Coast DHB Women’s Health Gynaecology Service. Wellington.
Gulli, L. F. and Odle, T. G. (2006) Hormone Replacement Therapy. The Gale Encyclopedia of Medicine, Third Edition. Jacqueline L. Longe, Editor. Farmington Hills, MI. Thomson Gale.
Ministry of Health (2003). HRT (Hormone Replacement Therapy). Ministry of Health. Wellington.
New Zealand Guidelines Group (2004) Hormone Replacement Therapy: Evidence-based Best Practice Guidelines. Pamphlet. New Zealand Guidelines Group.
Last Reviewed – 27 June 2013 


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