Serum Folate and Cobalamin Levels in Women Using Combined Contraceptive Vaginal Ring

Abstract

Introduction !The use of hormonal contraceptives is widespread throughout the fertile period from adolescence to perimenopause [1][2][3][4][5][6][7][8]. A wide variety of formulas [9][10][11], application methods [12][13][14][15] and therapeutic regimes [16][17][18][19][20][21][22] have been developed and assessed. The information that is available in the literature concerning the serum levels of folate (folic acid) in women using oral contraceptive pills is still somewhat conflicting. Some studies have shown diminished serum or plasma concentrations of folate in users of oral contraceptives when compared to controls [23,24], whereas others have found similar levels of folate in oral contraceptive users and non-pregnant female volunteers [25][26][27][28][29]. These divergent observations are hard to reconcile. It should be mentioned, however, that the folate concentration in serum and, to a lesser extent, in the erythrocyte is dependent on fasting and nutritional status, eating habits and recent vitamin supplementation, and that previous studies may not have been able to control all theses confounding factors. In addition, the process of handling and storage of blood samples has to be Abstract ! Purpose: The aim of our study was to evaluate the effects of combined contraceptive vaginal rings on serum concentrations of folate and cobalamin in healthy users. Material and Methods: Case-control study on cobalamin and folate status of 45 healthy female nulligravidae using a combined contraceptive vaginal ring for > 3 months and 45 healthy controls. Factors interfering with vitamin metabolism were thoroughly controlled. Results: Cobalamin and folate levels did not differ between the groups. Vegetarian diet, smoking or obesity did not have a significant influence. Conclusions: The use of a combined contraceptive vaginal ring provides an appropriate hormonal contraception in women with pre-existing cobalamin deficiency or restrictive diet habit in order to avoid interferences between vitamin B 12 metabolism and exogenously applied estrogens. Zusammenfassung