Women with dysmenorrhea on the first day of menstruation need precise diagnosis and the main reasons are as follows: 1, poor excretion: women with poor menstrual blood discharge on the first day of menstruation may have cervical orifice erosion and cervical orifice narrowing, leading to dysmenorrhea; 2, hormonal changes: during and before and after menstruation, hormone levels fluctuate dramatically, including large changes in estrogen and progesterone in the body, which can trigger pelvic organs and mucous membrane congestion and stasis, causing women to experience dysmenorrhea; 3, cold: women may not adapt to the first day of menstruation, especially cold in life, which in turn can lead to dysmenorrhea symptoms.