Avoid Falsely Accusing Female Athletes Who Use Levonorgestrel of Doping

Athletes are explicitly responsible for everything they consume, which may be an issue when the metabolic pathways of prohibited and non-prohibited compounds intersect. This was the case when 18-methyl-19-noretiocholanolone, an 18-methyl-19-nortestosterone metabolite, was detected in a sample of an athlete that had used an emergency contraceptive pill containing levonorgestrel. Six women were recruited to this study to elucidate the link between 18-methyl-19-noretiocholanolone and levonorgestrel. After providing a pre-treatment urine sample, one tablet of NorLevo, 1.5 mg, was ingested and six additional urine samples were collected. The samples were analysed with GC-MS/MS after extraction and derivatisation. In all six participants, 18-methyl-19-noretiocholanolone could be detected at 1.5-2.5 ng/mL with a t_max of 2 h. The presence of 18-methyl-19-noretiocholanolone was in all samples accompanied by levonorgestrel and its metabolite tetrahydronorgestrel, the latter being present at highest concentrations (60-300 ng/mL) up to 48 h post intake. Conclusively, this study demonstrates a metabolic link between 18-methyl-19-noretiocholanolone and levonorgestrel, confirming the need to verify the absence of levonorgestrel or its markers before reporting an adverse analytical finding.