A prospective, controlled trial of six forms of hormone replacement therapy given to postmenopausal women

This study was undertaken to investigate the effect of various forms of hormone replacement therapy (HRT) upon postmenopausal women while controlling as many variables as possible. It was felt that the age, duration of amenorrhoea and the general health of the patients should be as comparable as possible and that each patient should provide her own pretherapy and post-therapy control data. In addition, it was felt that any placebo effect should be investigated and the patients were therefore randomly allocated to placebo tablets or one of six available forms of HRT. The age/sex registers of two large general practices were scrutinized and all women between 49 and 54 years of age were asked to cooperate; for a variety of reasons only 56 women were suitable and willing to take part in the project, yielding 8 women for each of the seven possible therapy groups. Blood samples were taken at 7-day intervals three times before therapy was given and the mean of the three values was used as the control value. The women returned on day 21 of each subsequent therapy cycle for six consecutive months and finally three months after discontinuing therapy. From the data the following broad conclusions can be drawn: (i) some women have classic symptoms of hot flushes and sweating despite high endogenous oestrogen concentrations; (ii) vaginal cytology is a relatively poor indicator of endogenous oestrogen status; (iii) while follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentrations are reduced on HRT neither is decreased to anywhere near premenopausal values while prolactin is unaffected; (iv) plasma cholesterol levels are reduced on HRT, the pulse rate is slower and both systolic and diastolic blood pressure are reduced to a small but significant extent; (v) there is no adverse effect upon blood clotting; and (vi) most women experience significant or complete relief of symptoms on all forms of HRT as do some women taking a placebo. The combined preparations containing an oestrogen and progestogen produced vaginal bleeding in only 80 per cent of the women. Thus protection by regular endometrical shedding may not be afforded to all women. As vaginal bleeding is unacceptable to most women if they can achieve the same symptomatic relief without inducing menstruation, it is suggested that women have a low dose oestrogen preparation prescribed cyclically for 6 to 12 months. If therapy is to be maintained for a longer time, uterine curretage should be undertaken at regular intervals to exclude the possibility of endometrial carcinoma developing.