However, women on HRT generally develop lower grade, less aggressive breast cancer and have better survival chances. This, at least in part, is probably due to the fact that women on HRT are monitored more closely and the cancer, if it is developing, is detected earlier.

The possible development of breast cancer is linked to the duration of use, and albeit to a lesser degree, to dosage. The risk only increases after five years of usage.

The so-called natural hormones are phytoestrogens, which means oestrogen-like compounds found in plants. Isoflavones and lignans are the commonest forms of available phytoestrogens. They are not necessarily better than conventional HRT. Moreover, they need to be digested and broken down to be converted into the active ingredient/s.

It is problematic that phytoestrogens are not subject to control by the Medicines Control Council and as they are not standardised, one cannot always be certain about the amount of oestrogenic activity. They may, for example, contain too little oestrogen to protect against osteoporosis.

Transdermal routes of administration are available for oestrogen and for progestogen in the form of patches. They are more expensive than oral preparations. Implants are available as oestrogen and testosterone, but should be reserved for special indications in hysterectomised women. An oestrogen gel is also available for application to the skin and in some countries, as a nasal spray.