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

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 B₁₂ metabolism and exogenously applied estrogens.