[Progestagens and bones]

Gestagens when administered alone to menopausal women, (19 nortestosterone or progesterone derivatives) suppress loss of mineral content. But often a slight bone loss is observed, in contrast to the effect of oestrogenotherapy. 19 norpregnane derivatives seems to protect against bone loss. Progestagen may enhance bone formation without decreasing bone resorption. Administered together with oestrogens, gestagens have demonstrated either a decrease in biochemical estimates of bone loss or a radiologically positive effect. Progestogens alone in premenopausal women have various effects. In the case of contraception by injectable MPA the bone mass tend to decline as a result of hypoestrogenism. In summary gestagens seem to have on bone mass a rather favourable effect, which nevertheless is weaker than that of oestrogen.