Oxidative stress, vitamin E and progestin breakthrough bleeding

Endometrial bleeding problems can be the major reason for discontinuing pro gestin-only contraception, In this study the endometrial angiogenic respons e in Norplant users was found to be lower than in women with normal menstru al cycles. These disturbances in angiogenic response may be caused by oxida nt-antioxidant imbalance in the endometrium. The aims of this study were to investigate the effect of progestin-only contraceptives on blood concentra tions of lipid peroxide and vitamin E, and the effect of vitamin E suppleme ntation on endometrial angiogenic response in vitro. The subjects for this study were Norplant users, depo-medroxy-progesterone acetate (DMPA) users, and controls. Circulating lipid peroxide and vitamin E concentration was me asured by routine methodology. Endometrial angiogenic response was assayed using an endothelial cell migration assay. The results showed that the bloo d concentrations of lipid peroxide from Norplant users with bleeding proble ms were significantly higher than normal menstrual controls (P < 0.05) and supplementation of vitamin E (in vitro) increased the endometrial angiogeni c score. Blood concentrations of lipid peroxide were significantly increase d (P < 0.05), and the blood concentrations of vitamin E were significantly decreased (P < 0.05) after 3 months exposure to Norplant or DMPA, The endom etrial angiogenic scores in Norplant and DMPA users were significantly lowe r than in controls (P < 0.02). It is concluded that in progestin-only contr aceptive users, higher lipid peroxide and lower vitamin E concentration may cause endometrial cell damage and decrease the endometrial angiogenic resp onse. It is suggested that vitamin E supplementation may counteract these u nwanted side-effects.