Levonorgestrel effects on serum androgens, sex hormone-binding globulin levels, hair shaft diameter, and sexual function.

Objective: To determine the effects of levonorgestrel (LNG) on serum androgens, sex hormone-binding globulin (SHBG), hair shaft diameter, and sexual function in women.

Design: Substudy of a prospective randomized double-blind study in women using an LNG SC implant (LNG-SI), who were treated with doxycycline or placebo.

Setting: Medical school department of obstetrics and gynecology.

Patient(s): Forty women were enrolled; 36 completed the study.

Intervention(s): Participants were randomized to doxycycline 20 mg or an identical placebo orally twice a day after LNG-SI insertion.

Main Outcome Measure(s): Serum levels of total T (TT), free T (FT), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT), androstanediol glucuronide (AG), SHBG, and LNG; hair shaft diameter; and sexual function using the Brief Index of Sexual Function for Women and the Arizona Sexual Experiences Scale were assessed.

Result(s): Serum TT, A, DHT, DHEAS, and SHBG declined after LNG-SI insertion. No changes were found in FT, AG, hair shaft diameter, or sexual function. Serum LNG correlated with SHBG levels. There were no differences between the placebo and doxycycline groups.

Conclusion(s): LNG reduced serum TT, A, DHT, DHEAS, and SHBG but had no effect on sexual function or markers of androgen bioactivity.