The governing body, formerly the International Swimming Federation better known as FINA, created headlines in June last year when it effectively banned transgender women from competing in its women's events.

The status of transgender athletes' inclusion in sport has proved an increasingly divisive issue since then, with International Federations such as World Athletics and the International Cycling Union adopting bans of their own on trans women who have gone through puberty from women's competitions.

World Aquatics pledged to create an open category aimed at including transgender athletes at its events, and this was due to feature for the first time on a "pilot basis" at the opening World Cup of the year in the German capital from Friday (October 6) to Sunday (October 8).

However, it reported no registrations were received for open category events in the 50 and 100 metres distances across all strokes, which were scheduled alongside the men's and women's events.

Despite the cancellation of open category events, World Aquatics still plans to offer them at a future events too.

"The World Aquatics Open Category Working Group will continue its work and engagement with the aquatics community on open category events," it said.

"Even if there is no current demand at the elite level, the working group is planning to look at the possibility of including open category races at masters events in the future."

Critics have argued banning athletes from the category with which they identify is discriminatory, but supporters claim it safeguards fairness in women's sport.

In November 2021, the International Olympic Committee (IOC) approved new guidelines which granted increased flexibility to International Federations to set their own policy.

The IOC has been accused by critics of passing the buck on the issue, but President Thomas Bach has insisted there cannot be a "one-size-fits-all" approach.