Adherence to Hormone Replacement Therapy: A Longitudinal Study Using the Theory of Planned Behaviour

The aim of this longitudinal study was to assess the stability and determinants of the intention to adopt HRT over a one-year period using the Theory of Planned Behaviour. At baseline, a total of 644 middle-aged premenopausal women who had never used HRT, were recruited. At follow-up, 417 women completed an interview to assess any change in their reproductive status and in their behavioural intention. Among women who stayed premenopausal (n = 172) and among those who became perimenopausal (n = 209), the intention to adopt HRT was quite stable over the one-year period. However, being perimenopausal had a significant effect on the intention to adopt HRT at follow-up, as did subjective norm, perceived behavioural control and moral norm measured at baseline. Attitude towards HRT did not have a significant effect on the intention to adopt HRT one year later. Therefore, interventions to support women's decision-making about HRT should be tailored to their menopausal status and take into account their perception of social pressure to perform, control over this behaviour and moral obligation.