Former Boston and Chicago Marathon winner Rita Jeptoo's two-year doping ban has been doubled after the Court of Arbitration for Sport (CAS) upheld an appeal from the IAAF.
Jeptoo triumphed in Boston and Chicago two years ago, but tested positive for the performance-enhancing drug EPO in an out-of-competition test prior to the latter race.
Athletics Kenya imposed a two-year suspension, yet the IAAF appealed to CAS, requesting a four-year sanction - due to "aggravating circumstances" - and the disqualification of Jeptoo from the 2014 race in Boston.
CAS has now ruled in the governing body's favour, meaning Jeptoo, 33, will remain banned until October 2018.
A statement from CAS read: "In coming to its decision, the panel found to its comfortable satisfaction that the athlete used rEPO [recombinant EPO] over a period of time to enhance performance.
"The undisputed source of the rEPO found in her sample of 25 September 2014 was an injection given to her by a doctor. The athlete provided various differing accounts of the circumstances leading up to the injection and also regarding her relationship with that doctor.
"According to the applicable rules, the minimum period of ineligibility in this situation is a sanction of two years but can be increased to up to four years in the case of aggravating circumstances.
"The panel is comfortably satisfied that there are aggravating circumstances in the case at hand as it was obvious to the panel that the athlete used rEPO as part of a scheme or plan.
"The evidence for this includes inter alia her long relationship with the doctor in question, her multiple visits to see him, that her rEPO use was consistent with her competition calendar, that she hid the visits to the doctor in question from her manager and coach, as well as her deceptive and obstructive conduct throughout the proceedings."