Changes in carbohydrate tolerance during long-term oral contraception

An intravenous glucose tolerance test (GTT) was given to 116 women--82 nondiabetic subjects (NDS) and 34 diabetes suspects--before they received Ovulen for oral contraception. Subjects were followed for 1 to 4 years during Ovulen therapy. Twenty women using an intrauterine device showed no changes in glucose tolerance. Prompt, significant decline in tolerance was noted in NDS, persisting for the duration of the study. At least one abnormal test, indicating chemical diabetes, was noted in 13 per cent of the NDS. Similarly, prompt decline in tolerance, although not statistically significant, was observed in the suspect group. Fifteen per cent of suspects had at least one abnormal test. Chemical diabetes persisted during Ovulen therapy in suspects but not in NDS. No overt diabetes occurred. Based on greater concern regarding suspects, a procedure for monitoring carbohydrate tolerance is proposed for this group.