Oral contraceptive use and glucose metabolism in a national sample of women in the United States

Objective: This study was undertaken to determine whether users of oral contraceptives in a nationally representative population of US women had elevated levels of measures of glucose metabolism. Study Design: Cross-sectional data from the Third National Health and Nutrition Examination Survey (1988-1994) included hemoglobin A1c levels and fasting glucose, insulin, and C-peptide levels. Means were compared among those who had never used oral contraceptives, current users of oral contraceptives, and former users of oral contraceptives, with and without adjustment for potential confounders. Results:The vast majority of current users of oral contraceptives were using low-dose estrogen formulations. The two most common preparations were a triphasic formulation containing 0.035 mg ethinyl estradiol and 0.5, 0.75, and 1 mg norethindrone (23.9%) and a monophasic formulation containing 0.035 ethinyl estradiol and 1 mg norethindrone (20.7%). Current users of oral contraceptives did not have elevated values for any of the four measures of glucose metabolism. Hemoglobin A1c level and fasting glucose, insulin, and C-peptide levels were not related to duration of current use, age at which use began, or major formulation type. Among women who were former users of oral contraceptives there was no evidence of higher values among those who had recently ceased use. Conclusion: Oral contraceptive formulations currently available in the United States are not associated with an adverse glucose metabolic profile. (Am J Obstet Gynecol 2000;183:389-95.)