Treatment of endometriosis with Implanon versus GnRH agonists: effect on insulin sensitivity

Treatment of endometriosis with Implanon versus GnRH agonists: effect on

insulin sensitivity

A. Cagnacci, A. Tirelli, M. Cannoletta, D. Pirillo, S. Malmusi, D.

Radi, A. Volpe

Department of Obstetrics Gynaecology and Paediatrics, University of Modena,


Objectives: Medical therapy is usually performed after surgical

laparoscopic treatment for moderate-to-severe endometriosis. GnRH agonists, are

usually administered for the short-term, and oral contraceptives for the

long-term treatment of endometriosis. Oral contraceptives may induce metabolic

modifications among which a reduction of insulin sensitivity (SI). Beside the

progestin, the estrogenic component of the oral contraceptive may impair SI. In

this study we wanted to evaluate the effect of a progestin only administration

on SI of women with endometriosis, in comparison to GnRH analog-treatment.

Design & Methods: The study was performed in 26 women with

endometriosis that after laparoscopic surgery were randomised to receive a GnRH

analogue at the dose 3.75/28 days for 6 cycles (leuprorelin; Enantone, Takeda)

or a subcutaneous single rod progestin implant (etonogestrel; Implanon, Akzo

Nobel). In each woman SI was evaluated prior to treatment in the early

follicular phase of the first menstrual cycle and after 5 months of treatment.

SI or insulin-independent glucose utilisation (Sg) was investigated by the

minimal model method applied to a frequently sampled i.v. glucose tolerance


Results: SI was not significantly modified by the GnRH-analog

(5.29+1.29 vs. 3.99+0.8) and was significantly decreased by the progestin

implant (5.73+1.12 vs. 3.95+0.77; p50.05). Sg, fasting glucose, insulin,

C-peptide and C-peptide/insulin were not modified by either treatment.

Conclusions: As previously reported for oral contraceptives, the

administration of a progestin only contraceptive by subcutaneous implant is

associated with a slight deterioration of SI, with no modification of fasting

glucose control.

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