The women's world marathon record-holder had her ban reduced by one year after admitting guilt and accepting the sanction.

Ruth Chepngetich, the women's world marathon record-holder, has been banned for three years after an investigation by the Athletics Integrity Unit.

The 31-year-old Kenyan, who won last year's Chicago Marathon in a record-breaking 2:09:56, tested positive for the prohibited substance hydrochlorothiazide on March 14, 2025.

Hydrochlorothiazide is a diuretic and used clinically to treat fluid retention and hypertension. It may also be abused to mask the presence in urine for banned drugs.

Under WADA’s technical requirements for laboratories, HCTZ has a minimum reporting level of 20 ng/mL in urine, meaning findings below this concentration are reported as negative. The AIU state that Chepngetich had an estimated concentration of 3800 ng/mL in her urine.

When initially interviewed by AIU investigators on April 16, Chepngetich didn't provide an explanation for the positive test. To rule out the possibility of contamination, all the supplements and medications she had taken in the lead up to the positive test were collected. Her mobile phone was also copied for analysis.

At a subsequent interview on July 11, Chepngetich was confronted with evidence acquired from her mobile phone, indicating a reasonable suspicion that her positive test may have been intentional.

This included "a screenshot of a WhatsApp message the athlete received about testosterone" as well as "messages related to unidentified third parties working on 'programs' possibly related to doping" and "an image showing oxandrolone" [a banned anabolic androgenic steroid].

The investigation found that the person who sent Chepngetich the whatsapps of testosterone was another athlete she corresponded regularly with.

During this interview, Chepngetich was also informed that all the supplements and medications that had been taken for analysis at a WADA-accredited laboratory came back as negative for HCTZ.

She maintained her position that she could not explain the positive test and that she had never doped.

Then, on July 31, Chepngetich wrote to the AIU to state that she'd been taken ill two days before the positive test [March 12] and had taken her housemaid’s medication as treatment, showing a photo of the medication blister pack which was marked 'hydrochlorothiazide'.

The Kenyan, who also won the world marathon title in Doha in 2019, added that she forgot to disclose this incident to the AIU investigators.

Even though the standard sanction for a positive HCTZ test is a two-year ban, the AIU concluded that Chepngetich was "reckless" in taking her housemaid’s medication and that her actions equated to "indirect intent", which carries a four-year ban.

As Chepngetich admitted guilt and accepted the sanction within 20 days, the ban was subsequently reduced to three years.

The AIU will continue to investigate the suspicious material recovered from Chepngetich’s phone to determine if any other violations have occurred.

All of Chepngetich's results since March 24, 2025 have been disqualified, meaning her world record – which has been ratified – still stands.