Carbohydrate metabolism before and after Norplant removal

Changes in carbohydrate metabolism, measured by oral glucose tolerance test, were studied in Norplant users before and after removal. The mean area under the glucose curve rose from 24.7 min mmol/L before Norplant insertion to 35.1 min mmol/L before removal and decreased to 26.1 min mmol/L four weeks after Norplant removal. The areas before insertion and after removal were not statistically different (95% confidence interval -3.3 to 0.56, P = 0.16). The mean areas under the insulin curves before insertion (53.14 min uU/L) and after removal (59.46 min uU/L), however, were significantly different (95% confidence interval -7.64 to -5.0, P less than 0.0001). We conclude that changes in carbohydrate metabolism induced by Norplant are reversible once the implants are removed. While the changes in glucose induced by Norplant returned to pre-insertion levels within 4 weeks after removal, insulin changes were slower to return to pre-insertion values.