Hormone Replacement Therapy
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 underactive thyroid gland is treated with thyroid hormone and diabetes is treated with insulin. The ovary makes oestrogen, progesterone and some male hormone and 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 not had a hysterectomoy. The reason for this is that oestrogen on its own can cause cancer of the uterus and this is completely prevented when progesterone is given. Progesterone is usually given at monthly intervals to bring on a menstrual withdrawal bleed. Male hormone very rarely has to be replaced, as it is also made by the adrenal gland, but it does have a role in the body to improve sex drive.
Symptoms of oestrogen deficiency
A lack of oestrogen can cause changes in mood (depression and poor concentration), a reduction in energy, skin elasticity, breast size and vaginal dryness. Perhaps the most common symptom of oestrogen deficiency is that of flushing and this can often feel like intolerance to heat. In addition to these symptoms of oestrogen deficiency, we must also consider hidden chages which can effect later health. In particular, a lack of oestrogen causes thinning of the bones (osteoporosis) and early heart disease. That is, a bone fracture or heart attack in later life can be caused by a lack of oestrogen.
Risks of HRT
Recently we have learned that there is a higher risk of blood clots in women taking HRT even the natural oestrogens. There is, however, no higher risk of stroke in women on HRT. There is no excess risk of cancer of the uterus with HRT as long as progesterone is also given, to provide a menstrual bleed. In those younger women whose ovarian function tends to fluctuate, there is no adverse effect on future fertility by taking lower dose HRT.
One question that remains is the issue of breast cancer. Several studies have suggested that breast cancer is more common in women who have taken HRT for more than 10 years. There are good theoretical reasons why oestrogen might cause breast cancer. It is possible, therefore, that by extending the "oestrogen years" by more than 10 years (that is, bt taking HRT for ten years, between the ages of 50 and 60) breast cancer becomes slightly more common.
It is likely that women who experience an early menopause are at a reduced risk of breast cancer and, therefore, replacing oestrogen merely returns that risk tonormal. In the situation of women who undergo the menopause before the age 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. If there is a strong family history of breast cancer, then it is wise to have regular breast checks and consider mammography.
Conjugated Oestrogens (Premarin and Prempak)
Conjugated oestrogens have been the most widely used type of natural oestrogen and most of the safety information we have about HRT is obtained from the use of these tablets. Conjugated oestrogens are extracted from the urine of pregnant mares and, although there has been some concern about the well being of these animals, there is also reassurance from the pharmaceutical company that the farming conditions are satisfactory. It is treatment with these tablets that gives us most of the information on the prevention of oseoporosis and heart disease.
Other Natural Oestrogens (eg. Cyclo-progynova, Climagest, Nuvelle, Trisequens, Tridestra, Kliofem)
Most other tablet forms of HRT contain oestrodiol valerate or a similar compund and these tablets are extracted from soya beans. While these preparations appear to be the same strength as conjugated oestrogen tablets, we do not yet have the many years of scientific research to be certain of the risks and benefits of this treatment although they are likely to be as effective as conjugated oestrogens. Two new preparations in this group have recently been introduced to reduce the number of menstrual periods in women on hormone replacement therapy. Tridestra provides a period every three months and Kliofem provides continuous oestrogen and progesterone tablets, resulting in no periods in some women.
All oral contraceptive pills contain ethinyloestradiol, a strong synthetic oestrogen designed to prevent ovulation. Oral contraceptive pills have often been used as HRT in young women. The oral contraceptive pills however, because they are stronger than natural oestrogens, do carry a small increased risk of blood clotting (thrombosis) which does not occur with oestradiol valerate or conjugated oestrogens. For many women with oestrogen deficiency, the oral contraceptives may be unnecessarily strong for use as HRT.
Tibolone is a synthetic steriod which has some oestrogen-like and some progesterone-like activity. This preparation is designed to prevent the symptoms of oestrogen deficiency without causing menstrual bleeding. Lack of menstrual bleeding is likely only if periods have ceased for more than one year. It seems to be effective in preventing osteoporosis but the long term effects on the risk of thrombosis, heart attacks and breast cancer are unknown.
Skin Patches and Oestrogen Gel
(eg. Estrapak, Estracombi, Evorel, Femapak, Fematrix, FemSeven, Pro-Gynova TS)
There are now several skin patches available on the market, which allow oestrogen to be slowly absorbed through the skin. The design of these preparations is improving and the newer ones tend to be less irritating to the skin. Oestrogel works in a similar way to the patch and is applied to arms, shoulders or thighs each day. The patches are helpful in reducing the side effects of the tablet forms of HRT, in particular, headache, nausea and a rise in blood pressure. Patches are also particularly useful for women with liver disease or raised triglyceride levels.
Oestrogen implants have been very popular in previous years, when skin patches were not available. They involve a minor surgical procedure, where the implant is inserted beneath the skin of the abdomen or buttock once every six months. Implants are used less frequently now that patches are available, for two maon reasons. Firstly, some women seem to "get used" to implants and find they need higher and higher doses and secondly, if side effects occur, it can be difficult to remove the implant.
For women who have not had a hysterectomy, any oestrogen treatment must be combined with progesterone, either in tablet form or with a second patch, in order to provide a menstrual bleed. Without the use of progesterone, oestrogen treatemnt on its own carries an increased risk of cancer of the uterus but with progesterone this risk is completely removed. Some new HRT preparations use progesterone only every three months or continuously to reduce or prevent menstrual withdrawal bleeds. The side effects of progesterone treatment include premenstrual symptoms of mood change, bloating and breast discomfort. All progesterone preparations are synthetic. 'Natyral' progesterone cream has been used in the US and there is no information yet to say this is better than the synthetic products.
Reproduced with kind permission of Dr Gerard Conway, The Middlesex Hospital, Mortimer Street, London, W1N 8AA.