Oestrogen replacement therapy for prevention of osteoporosis after oophorectomy

The value of oestrogen therapy in the prevention of osteoporosis after oophorectomy was assessed in 114 middle-aged women who participated in a double-blind controlled trial of mestranol in an average daily dose of 23 mug. The skeletal response to treatment was measured by a photon absorption technique. Where treatment was started within two months of operation subsequent bone mineral loss was prevented. Treatment started three years after oophorectomy caused a highly significant increase in bone mineral content. When treatment was delayed for six years mestranol failed to prevent subsequent bone mineral loss with age. These effects occurred independently of the associated humoral changes in calcium and phosphorus homoeostasis. Mestranol in this dosage appeared to be relatively safe, but it is too early to evaluate the long-term hazards of such therapy.