If you have decided that hormone replacement therapy (HRT) is the right choice for you, the next step is deciding which form is going to be the best. Dr Lesley Hickin looks at the options.

HRT is a medication that you will be taking for a minimum of a few months and possibly for several years. You should therefore talk through all your worries with the person prescribing the medication and make sure that you understand the benefits, risks and potential long-term problems associated with your HRT. Don't be afraid to go back to your doctor if you develop side effects or unusual bleeding.

HRT considerations
Most women will need to take both an oestrogen and a progestogen. If you have had a hysterectomy you will only need to take oestrogen but if you still have your uterus you need to protect yourself from the increased risk of endometrial cancer that taking oestrogen alone will confer.

If you are in the perimenopause or within a year of your last period you will be prescribed progestogens cyclically, in other words you will take them for 12-14 days each four weeks and when you stop taking them you will bleed for a few days. In this way you will appear to have a regular period. You may not then know when your natural menopause occurs.

Types of treatment
HRT is available in tablet and skin patch forms, with different blood levels of oestrogen being reached depending on your personal metabolism. The highest levels are achieved by having an implant, which is a small pellet of hormone inserted under the skin using a local anaesthetic.

You can also apply oestrogen to the vagina using creams and vaginal tablets (pessaries). This type of treatment is most useful for symptoms of vaginal dryness or soreness. It can also be useful for women who get a lot of cystitis symptoms after the menopause. It isn?t usually useful for other menopausal symptoms such as flushes and sweats, as only tiny amounts of oestrogen get into the blood stream from vaginal oestrogen preparations. This should only be used in the short term (3-6 months) at low doses, after which time it is recommended that treatment is stopped to assess whether it is still necessary. If symptoms of vaginal dryness and soreness recur after stopping treatment, then it can be resumed for a further 3-6 months. In higher doses it may be absorbed into the bloodstream and have an adverse effect on the lining of the uterus. If you need to use it long-term you need to take a cyclical progestogen.

Common types of HRT delivery
Most people in the UK take HRT by mouth in tablet form, which is convenient and flexible. It is easy to change if problems occur. A large proportion of the absorbed oestrogen is inactivated when it passes through the liver so the dose has to be higher than if the oestrogen is absorbed straight through the skin in the form of a patch. The tablets can be oestrogen alone or combined oestrogen and progestogen.

Patches are also convenient to use and are popular. The new matrix patches give less skin irritation than the older type, which have a higher alcohol content.

Implants are popular with gynaecologists and are often prescribed at the time of hysterectomy and ovarian removal. They give gradually decreasing levels of oestrogen over a few months and need periodically replacing. They can be combined with testosterone implants for women who suffer from reduced libido after the menopause. They are not without problems, as there's a tendency to need the implants replaced earlier each time. The tissues seem to become less responsive to the hormones.

A recent addition to the HRT treatment options is the nasal spray. You squirt one dose a day up your nose and the oestrogen is absorbed to give you symptom relief for 24 hours. There are said to be fewer side effects with this way of taking it, but some women have reported problems with a sore and blocked nose.

Other options

Another option is continuous combined HRT. These tablets contain a constant amount of oestrogen and progestogen and mean that you do not have a regular bleed. They should only be prescribed when you are at least 12 months after your last natural period or you may experience spotting and irregular bleeding. The problem is that you may not know when this occurs when you have been taking HRT for some time. For this reason doctors tend to wait until you are 54 or older to give this type of HRT.

Who can take HRT?
Some women should not take oestrogens, though not as many as was once thought. Here are a few reasons.

• Unexplained vaginal bleeding until you know there is no serious cause
  
• Active breast cancer (women who are in remission and have no active disease may be able to take it under close medical supervision)
  
• Severe or active liver diseaseM

• Endometriosis - may be reactivated by HRT
  
• Fibroids - may enlarge and cause troublesome bleeding
  
• Women with a past problem with blood clots in veins (thromboembolism) need to be tested to make sure they are not at risk of developing further clots, which are slightly more common on HRT