As an 11-year-old in Poland, Aleksandra Shelton saw her mother competing in a fencing competition on television. Intrigued by the sport and the allure of also appearing on TV someday, she built a saber fencing career that far surpassed her mother’s aspirations.

A decade later, Shelton won a bronze medal at the 2003 world championships. Then she took gold at the 2004 and 2008 European championships. She has competed in the past four Olympics for Poland. And she anticipated that this summer in Tokyo she would become only the fourth Polish woman — and about the 220th woman worldwide — to participate in five or more Games.

But Shelton, a dual citizen who is married to an American serviceman, encountered what she said was age and gender discrimination from Polish fencing officials after the birth of her first child three years ago. So she made a desperate attempt at nation-switching, hoping to head to her fifth Games as an American. Poland, however, has blocked the change, trapping Shelton between the two countries, leaving her unable as of now to compete in Tokyo for either.

Sandwiched by the heated politics of athletes’ rights and the baroque rules of Olympic eligibility, she is facing the sporting complications that can confront women who become mothers.