RESUMO
AIM: Women who developed vestibulodynia (vulvar vestibulitis) while taking combined hormonal contraceptives (CHCs) and a control group of women were tested for polymorphisms of the gene coding for the androgen receptor (AR) that is located on the X chromosome. STUDY DESIGN: DNA from 30 women who developed vestibulodynia while taking CHCs and 17 control women were tested for the number of cytosine-adenine-guanine (CAG) trinucleotide repeats in the AR. In addition, serum-free testosterone was tested in both groups. RESULTS: The mean number of CAG repeats in the study group was significantly greater than the control group (22.05 ± 2.98 vs. 20.61 ± 2.19, respectively; P = 0.025). This significant difference persisted when analyzing the CAG repeats from the longer allele from each subject. Among those who were taking drospirenone-containing CHCs, the mean calculated free testosterone was 0.189 ± 0.115 ng/dL in the study group and 0.127 ± 0.054 ng/dL in the control group, all of whom were taking drospirenone-containing CHCs (P = 0.042). CONCLUSION: In the study cohort, women who developed vestibulodynia while taking CHCs are more likely to have longer CAG repeats in the AR than women who took the same type of CHC but did not develop vestibulodynia. We speculate that the risk of developing CHC-induced vestibulodynia may be due to lowered free testosterone combined with an inefficient AR that predisposes women to vestibular pain.