"It's very normal," she explained.
Doctor Tsai said he had already been checking for endometriosis - which causes tissue that normally lines the uterus to grow outside the uterus - when the woman's coughing began.
Tests revealed that the disorder had caused tissue to grow inside her trachea - and that she was essentially choking on her menstrual fluid every time she had her period.
Doctor Tsai noted that while endometriosis is not that uncommon, it usually occurs around the individual's pelvis. In rare cases, it can happened in the abdomen, intestines, the trachea and even the nasal cavity, he added.
There are believed to be fewer than 50 documented cases in the world, Tsai said.
There is no known cure for endometriosis, but the young woman's symptoms can be treated with pain medication or surgery.