Progestins in the menopause.

While the benefits of progestin use in hormone replacement therapy (HRT) are well recognised as far as endometrial protection is concerned, their risks and drawbacks have generated controversial articles. The data related to the progestin effect on breast tissue has been interpreted differently from country to country. However it has been admitted that, according to the type of progestin used, the dose and duration of its application, a predominant antiproliferative effect is observed in the human breast cells. As far as breast cancer risk is concerned, most epidemiological studies do not suggest any difference between the estrogens given alone or combined to progestins in HRT. When the cardiovascular risk factors are considered, some molecules with a higher androgenic potency than others, attenuate the beneficial effects of estrogens on the lipid profile and the vasomotion as well. On the other hand, other progestins devoid of androgenic properties do not exert these deleterious effects. The epidemiological data does not suggest any negative effect of the progestins administered together with estrogens on cardiovascular morbidity or mortality. However, recent results suggest that in women with established coronary heart disease (CHD), HRT may not protect against further heart attacks, when the progestin selected possesses androgenic properties. Complying with the classic contra indications of HRT and selecting molecules devoid of estrogenic, androgenic, or glucocorticoid effect should allow a larger use of the progestins without any major drawback.