The Union Cycliste Internationale (UCI) announced it was halving the maximum permitted plasma testosterone for trans women to compete in the female category from 5 nmol/L to 2.5 nmol/L and doubling the period they must remain below that threshold before being allowed to compete from one to two years.
The rule change, which comes into force on July 1, may stop Bridges racing in women’s events on the “UCI international calendar” until the summer of 2024, denying her the chance to qualify for the next Olympics.
It was announced two months after British Cycling suspended its own trans policy amid a major backlash against Bridges’ plans to switch from racing in men’s events and take on the likes of Dame Laura Kenny at the National Omnium Championships.
The event had faced a rider boycott were Bridges allowed to compete a year after she began complying with the current rules.
Confirmation of the change also came three days before Fina, swimming’s world governing body, was expected to introduce new transgender rules.
Those could deny Thomas, who in March became the first trans woman to win a National Collegiate Athletic Association title, a place at Paris 2024 as well.
The UCI said in a statement: “In March 2020, the UCI published rules governing the participation of transgender athletes in events on the UCI International Calendar in the category corresponding to their new gender identity.
“Although these rules are stricter and more restrictive than those published by the International Olympic Committee (IOC) in 2015, the UCI has begun consideration on their adjustment following the publication of new scientific studies in 2020 and 2021.
“The principle of eligibility of transgender athletes (in particular female athletes, ie those who have made a transition from male to female) is based on the reversibility under low blood testosterone (the level commonly observed in ‘born female’ athletes) of the physiological abilities that determine sports performance, and on the time needed to achieve this reversibility.
“The latest scientific publications clearly demonstrate that the return of markers of endurance capacity to ‘female level’ occurs within six to eight months under low blood testosterone, while the awaited adaptations in muscle mass and muscle strength/power take much longer (two years minimum according to a recent study).
“Given the important role played by muscle strength and power in cycling performance, the UCI has decided to increase the transition period on low testosterone from 12 to 24 months. In addition, the UCI has decided to lower the maximum permitted plasma testosterone level (currently 5 nmol/L) to 2.5 nmol/L. This value corresponds to the maximum testosterone level found in 99.99% of the female population.
“This adjustment of the UCI’s eligibility rules is based on the state of scientific knowledge published to date in this area and is intended to promote the integration of transgender athletes into competitive sport, while maintaining fairness, equal opportunities and the safety of competitions.
“The new rules will come into force on 1st July. They may change in the future as scientific knowledge evolves.
“Moreover, the UCI envisages discussions with other international federations about the possibility of supporting a research programme whose objective would be to study the evolution of the physical performance of highly trained athletes under transitional hormone treatment.”
The UCI also published a paper written by its medical director, Professor Xavier Bigard, entitled: ‘The current knowledge on the effects of gender-affirming treatment on markers of performance in transgender female cyclists’.