Levonorgestrel-releasing intrauterine system as an adjunct to estrogen for the treatment of menopausal symptoms--a review.

Exogenous estrogen is an effective means of prevention for postmenopausal symptoms. Estrogen treatment should be combined with progesterone in non-hysterectomized women to prevent estrogen-induced malignant transformation of the endometrium. Progesterone supplementation using continuous combined estrogen + progesterone treatment may result in an increased incidence of breast cancer and cardiovascular disease. In addition, progesterone supplementation with sequential estrogen + progesterone treatment may cause immediate adverse effects, such as irregular bleeding and spotting, breast congestion, fluid retention, abdominal distention, and a change in lipid profile. All these effects are related, at least in part, to the progesterone component of the therapy.To avoid these complications, researchers are seeking safer progestational components and different modes of administration. In this article we review the findings on the use of the novel levonorgestrel-releasing intrauterine system as a therapeutic tool for localized, rather than systemic, progesterone administration in postmenopausal women.