A Prospective Study of Insulin Sensitivity and Glucose Metabolism in Women Using a Continuous Subdermal Levonorgestrel Implant System

Abstract

Objective: Decreased insulin sensitivity and deterioration in oral glucose tolerance curves habe been reported with oral contraceptive use, particularly with those containing levonorgestrel. However, the subdermal levonorgestrel systems release a lower dosage of steriod and avoid the first pass through the liver that occurs with oral administration. We hypothesized, therefore, that continuous subdermal levonorgestrel has no significant effect on insulin sensitivity and other indices of glucose metabolism.

Methods: Nine women desiring a subdermal hormonal contraceptive system were recruited for this longitudinal prospective study. Each subject underwent a 3-hour frequently sampled intravenous glucose tolerance test immediately before insertion and after 6 months of continuous ues. Insulin sensitivity and glucose effectiveness were determined using a mathematical minimal modeling approach. Glucose clearance and fasting and peak levels of glucose and insulin were examined as well. The matched-pair data were analzed using paired t tests.

Results: There was no significant change in insulin sensitivity, glucose effectiveness, glucose clearance, or fasting or peak insulin levels. Fasting glucose levels remained within a normal range.

Conclusions: Subdermal levonorgestrel appears to have no significant effects on tissue insulin sensitivity or glucose metabolism after 6 months of continuous use.