World athletics' governing body has appealed against the decision to clear Brazilian long-jumper Maurren Higa Maggi of a doping offence.
Maggi was the world's number one long-jumper before her ban
Maggi tested positive for the banned steroid clostebol in June but she claimed it stemmed from a substance used during a hair removal procedure.
She was subsequently cleared by Brazil's Superior Sports Tribunal.
But the International Association of Athletics Federations has appealed to the Court of Arbitration for Sport.
Maggi tested positive after winning gold at the Brazil Grand Prix last year and was given a two-year ban.
The 27-year-old missed the 2003 Pan-American Games but at an appeal she claimed the substance was one of the components of a pharmaceutical cream she used after cutting herself during a hair removal process.
The seven judges of the Brazilian Superior Sports Tribunal voted unanimously to
acquit her of wrongdoing in January.
Had the IAAF ratified her acquittal, Maggi would have been cleared to compete at the Athens Olympics in August.
The Court of Arbitration says it usually delivers its decisions within four months, meaning Maggi may yet be able to take part in the Olympics.