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.

Key Words: Levonorgestrel subcutaneous implant, sex hormone–binding globulin, serum androgens, hair shaft diameter, sexual function, testosterone