Caster Semenya has experienced yet another set back in her ongoing row with the International Association of Athletics Associations (IAAF).

The Swiss Supreme Court on Tuesday announced that it has overturned an earlier ruling to allow Semenya to compete in international events without taking medication to reduce her testosterone levels.

This is a result of the controversial ruling by the IAAF in May stating that female athletes with naturally high testosterone levels have to take hormone-reducing medications, compete with men, or increase their running distance.

The ruling only applies to the pole vault and the 400m hurdles, as well as the 400m, 800m, and 1,500m races.

Semenya competes in the 400m, 800m, and 1,500m races — and currently holds the 800m World Championship title.

She continued to compete internationally after the Court of Arbitration for Sport, which specialises in internal sports-related disputes, overturned in June the IAAF’s ruling while Semenya and her team appealed against the initial ruling.

Now that Semenya has to follow the IAAF’s regulations, and take medicine or stop competing against other women, she won’t be able to compete at the World Championships — being held in September in Doha, capital of Qatar.

Semenya has spoken out against  the IAAF’s regulations, and says they are an attack on her career.

In a statement released by her lawyers after the May ruling, Semenya said: “I know that the IAAF’s regulations have always targeted me specifically. For a decade the IAAF has tried to slow me down, but this has actually made me stronger.”

And the latest setback, Semenya says, won’t stop her from challenging the IAAF.

“I am very disappointed to be kept from defending my hard-earned title, but this will not deter me from continuing my fight for the human rights of all of the female athletes concerned,” she said in a statement.

Meanwhile, the IAAF, which has always insisted that the regulations are not a personal attack on Semenya, welcomed the decision by the Swiss court.

In a statement released through its website, the IAAF said: “This decision creates much needed parity and clarity for all athletes as they prepare for the World Championships in Doha this September.”

The statement added: “The IAAF will maintain its position that there are some contexts, sport being one of them, where biology has to trump gender identity, which is why the IAAF believes (and the CAS agreed) that DSD [differences of sexual development] Regulations are a necessary, reasonable, and proportionate means of protecting fair and meaningful competition in elite female athletics.”