Hormone Replacement Therapy
An information sheet on some medical aspects of HRT

This advice sheet was written particularly for young women who use HRT - for example those with Turner's syndrome, who have experienced an early menopause or who had pituitary disease as a child. Everyone has a different opinion about HRT and there may be disagreement with some of the content which is offered in the spirit of informal advice. Also, as new research emerges and new preparations are released, this information will require updating.

Hormone replacement therapy (HRT) is a phrase which describes the replacement of oestrogen to women whose own oestrogen levels are low. The body makes many hormones and in general, when a hormone is lacking it should be replaced. For example, an under active thyroid gland is treated with thyroid hormone and diabetes is treated with insulin. The ovary makes oestrogen, progesterone and some male hormone, testosterone. Most of the debate in this area relates to the use of oestrogen.
Progesterone has a very clearly defined role. Progesterone must be given to all women receiving oestrogen who have a uterus. The reason for this is that oestrogen given on its own can cause cancer of the uterus and this is almost completely prevented when progesterone is given. Progesterone is usually given at for 12-14 days each months to bring on a menstrual withdrawal bleed.
Male hormone, testosterone, very rarely has to be replaced as it is also made by the adrenal gland. Testosterone supplements have been shown to improve sex drive in women after removal of the ovaries but none of the preparations available in the UK are perfect for use in women.
Symptoms of oestrogen deficiency
A lack of oestrogen can cause changes in mood (depression and poor concentration), vaginal dryness and a reduction in energy, skin elasticity, and breast size. Perhaps the most common symptom of oestrogen deficiency is flushing - this can often feel like intolerance to heat. In addition to these symptoms of oestrogen deficiency, there are hidden changes which can affect health later on in life. In particular, a lack of oestrogen causes thinning of the bones, osteoporosis, and early heart disease. That is, a bone fracture or a heart attack in later life can be caused by a shortage of oestrogen.
Benefits of hormone replacement therapy
Oestrogen treatment is very effective at reducing and often completely preventing the symptoms of oestrogen deficiency. As regards osteoporosis, oestrogen can improve the density of bone and prevent bone loss, although the extent of the strengthening of bone is very variable. On average there is a 25- 50% reduction in bone fractures in women who have used HRT, compared to women who have never used HRT.
It had been thought that HRT might delay the onset of heart disease with estimates of a 30% reduction in heart attacks in HRT users. Recent reports , however, have shown that there is no benefit to the heart. These studies do show that taking HRT can reduce the risk of colon cancer and possibly Alzheimer's disease.
The side effects of oestrogen treatment include nausea, headaches, breast tenderness, a rise in blood pressure and weight gain. Usually, these side effects can be avoided by changing the type of preparation. Side effects of HRT are less with low dose preparations and with skin patch preparations.
Every woman is different - with over 50 types of HRT available in the UK it is hoped that every woman will find a suitable preparation. It is also possible to prescribe each component of HRT separately to individually tailor the mix of oestrogen, progesterone and testosterone. It may be necessary work through several types of HRT by trial and error and be prepared to make changes with time.
Risks of hormone replacement therapy
Recently, we have learned that there is a higher risk of blood clots in women taking HRT even with natural oestrogens. Blood clots can occur in the veins of the leg - a deep vein thrombosis. HRT should not be used if a thrombosis has happened in the past. The risk of stroke is also slightly raised in women on HRT.
There is no excess risk of cancer of the uterus with HRT as long as progesterone is also given. In young women whose ovarian function tends to fluctuate, there is no adverse effect on future fertility by taking low dose HRT.
Breast cancer is a common fear for women taking HRT. Several studies have suggested that breast cancer is more common in women who have taken HRT for more than ten years. There are good theoretical reasons why oestrogen might cause breast cancer. By extending the "oestrogen years" by more than ten years (that is, by taking HRT for ten years, between the ages of 50 and 60) breast cancer becomes slightly more common. Oestrogen replacement is not usually taken by women who have had breast cancer unless symptoms of a lack of oestrogen are particularly troublesome. If there is a very strong family history of breast cancer, then it is wise to have specialist advice and consider mammography. Mammograms most effective in older women and screening with mammography usually starts at the age of 45 - 50 in the UK - using HRT makes no difference to this screening policy.
HRT and young women
It is likely that women who experience an early menopause have a lower than average risk of thrombosis and breast cancer. Therefore, replacing oestrogen merely returns these risks to normal - just as if the ovaries were working normally. In women who undergo the menopause before the age of 40, it may well be safe, indeed advisable, to take HRT for more than 10 years, continuing at least until the age of the average menopause at 50.
In some young women with an early menopause there is a chance of pregnancy. If a pregnancy is not wanted then the best form of HRT might be the oral contraceptive pill. Alternatively, if HRT preparations are preferred, then barrier contraception should be used. If pregnancy is wanted then low dose oestrogen replacement will not prevent a miracle pregnancy happening - indeed, most women in this situation conceive while taking HRT. There is no risk to the baby and HRT can be stopped as soon as pregnancy is discovered as the placenta makes plentiful hormones.
If the chance of pregnancy is very low then HRT is generally better than the oral contraceptive because most forms of HRT provide oestrogen all the time instead of just for 3 weeks out of 4 with the pill. That is, symptoms of oestrogen deficiency can occur in the pill free week that is part of all combined oral contraceptives .