The former world 5000m and 10,000m champion will miss the 2026 track season after testing positive for Letrozole, which she was taking to treat a diagnosed medical condition.

Ethiopian endurance runner Gudaf Tsegay has been given a four-month ban after testing positive for Letrozole but successfully – and somewhat belatedly – arguing that she was using it to treat a genuine medical condition.

The 29-year-old, who has won world titles at 5000m and 10,000m and broken world records for 5000m and the indoor mile, was able to produce the medical papers to support her case, which led to a four-month ban being agreed instead of a longer punishment.

Letrozol lowers estrogen levels in the body.

The Athletics Integrity Unit says Tsegay has been banned "under a Case Resolution Agreement, after admitting to Anti-Doping Rule Violations (ADRVs) for the presence of a metabolite of Letrozole".

The AIU adds: "The 29-year-old Ethiopian was sanctioned under Rule 2.1 of the Anti-Doping Rules (ADR) relating to the Presence of a Prohibited Substance or its Metabolites or Markers in an Athlete’s Sample, and Rule 2.2 relating to Use or Attempted Use by an Athlete of a Prohibited Substance or a Prohibited Method.

"Tsegay’s period of Ineligibility will run from 1 June - the date the athlete accepted the Case Resolution Agreement - until 30 September 2026."

The AIU adds: "Following an out-of-competition test on 5 December last year, Tsegay returned a positive test for a metabolite of Letrozole - a Specified Prohibited Substance prohibited at all times under the WADA 2025 Prohibited List under the category of S4.1 Aromatase Inhibitors. She was subsequently notified of the potential ADRV by the AIU on 26 January 2026 and responded a day later explaining that she had been prescribed Letrozole to treat a diagnosed medical condition. She also produced supporting medical documents and evidence.

"On 17 February 2026, Tsegay submitted a Therapeutic Use Exemption (TUE) application to the World Athletics Therapeutic Use Exemption Committee (WATUEC), which subsequently confirmed that the athlete’s treatment met the requirements of Article 4.2 of the World Anti-Doping Agency’s (WADA) International Standard for Therapeutic Use Exemptions (ISTUE).

"Under Article 4.2, a TUE is granted if the athlete shows the prohibited substance is needed to treat a diagnosed medical condition; there is no reasonable permitted therapeutic alternative; and the therapeutic use of the Prohibited Substance will not produce any additional performance enhancement beyond a return to a normal state of health following treatment.

"While the conditions for a TUE under Article 4.2 were met, an application to WADA to exceptionally grant a retroactive TUE in this case under Article 4.3 ISTUE was rejected. Tsegay therefore entered a Case Resolution Agreement with the AIU and WADA, and a four-month ban was considered appropriate under Rule 10.6.1(a) ADR (No Significant Fault or Negligence). The length of the sanction was based on Tsegay’s degree of Fault, her prompt admission of the ADRV, and the fact she demonstrated that the presence of the metabolite of Letrozole in her sample met the criteria of Article 4.2, meaning she would have received a TUE if it had been requested in advance."