Avoid Falsely Accusing Female Athletes Who Use Levonorgestrel of Doping

Area of Science:

• Sports Science
• Biochemistry
• Analytical Chemistry

Background:

• Athletes bear full responsibility for ingested substances.
• Metabolic pathways of prohibited and non-prohibited compounds can intersect, leading to potential doping violations.
• 18-methyl-19-noretiocholanolone, a metabolite of 18-methyl-19-nortestosterone, has been detected in athletes' samples.

Purpose of the Study:

• To investigate the metabolic link between 18-methyl-19-noretiocholanolone and levonorgestrel.
• To determine if emergency contraceptive use can lead to the detection of 18-methyl-19-noretiocholanolone.

Main Methods:

• Six women ingested a 1.5 mg tablet of NorLevo (levonorgestrel).
• Urine samples were collected pre-ingestion and up to six times post-ingestion.
• Samples were analyzed using Gas Chromatography-Mass Spectrometry/Mass Spectrometry (GC-MS/MS) after extraction and derivatization.

Main Results:

• 18-methyl-19-noretiocholanolone was detected in all participants (1.5-2.5 ng/mL) with a Tmax of 2 hours.
• Levonorgestrel and its metabolite tetrahydronorgestrel were present in all samples.
• Tetrahydronorgestrel was found at the highest concentrations (60-300 ng/mL) up to 48 hours post-intake.

Conclusions:

• This study establishes a clear metabolic link between 18-methyl-19-noretiocholanolone and levonorgestrel.
• The findings underscore the necessity of verifying the absence of levonorgestrel or its metabolites before reporting an adverse analytical finding in athletes.
• This research is crucial for accurate doping control and athlete protection.