Oral contraception, mechanical contraception, and carbohydrate and lipid metabolism: a two-year study.

The carbohydrate and lipid metabolism of 100 women using an oral contraceptive (0.5 mg norgestrel + 0.05 mg ethinyl estradiol) and of 96 women using mechanical contraceptives was monitored over a 2-year period. The women had been screened for factors known to adversely affect carbohydrate and lipid metabolism. Two-hour oral glucose tolerance tests were performed at 6-month intervals during the study; serum insulin was determined at the same intervals in half the women. Triglycerides, total cholesterol, free fatty acids, and body weight were also measured. The study showed no significant differences in lipid metabolism nor in weight gain between women using oral or mechanical contraceptives. After 6 months the fasting glucose of women using oral contraceptives was significantly decreased; at 120 minutes, glucose and insulin levels were significantly increased in comparison to women using mechanical contraceptives. A greater percentage of oral contraceptive users had borderline-abnormal oral glucose tolerance tests but the abnormalities did not persist in the same individuals during the study. The incidence of a pathological oral glucose tolerance with oral contraceptives was 1%.