月经是子宫寂寞流的泪
[yuè jīng shì zi gōng jì mò liú de lèi]
The term '月经是子宫寂寞流的泪 (Menstruation is the womb's tear of loneliness)', conveys the painful experience women suffer when menstruating, metaphorized here through emotions like sadness. Thereby, it portrays menstrual cramps as a kind of sorrow that originates from loneliness inside women's bodies.