Why won't you suffer from dysmenorrhea after giving birth to a baby?

For women with primary dysmenorrhea, there will be no dysmenorrhea after giving birth to the baby, probably because the female has no baby before, the cervical canal is relatively narrow or the uterus is excessively bent, so when the menstrual cramps, menstrual blood discharge is not very smooth, so it will cause pain. However, after giving birth to a baby, the cervical canal will return to a normal state, and the uterus will not be excessively retroflex, so the menstrual blood is discharged smoothly during menstruation, so after giving birth to a baby, this type of female dysmenorrhea will naturally ease.