Women no longer have menstrual cramps after having children, probably because before having children, women are younger and their ovulation function is not stable, while at the age of normal childbirth, the function of endocrine will slowly improve and ovulation will be more vigorous. After childbirth, the cervical opening becomes relatively smooth and the menstrual blood flows out more smoothly, which will also reduce the symptoms of menstrual pain. After the birth of a child, women’s bodies are properly regulated and their physique improves, so that their endocrine secretions slowly become normal, which will also improve menstrual pain. As a woman’s uterus matures with age, the adrenaline nerves that govern the smooth muscles of the uterus disappear after childbirth, and the sensitivity of the smooth muscles of the uterus decreases, so the altered neuromuscular activity of women after childbirth will make the symptoms of dysmenorrhea disappear.