Amenorrhea is first divided into physiological or pathological. If it is physiological, it generally is not a major issue, but pathological cases must be treated symptomatically. For physiological amenorrhea, such as not menstruating for three months during the breastfeeding period, this is normal. It's mainly influenced by the secretion of prolactin from the ovaries, so it’s possible not to have menstruation during breastfeeding, and this is not a problem. Moreover, some people use medications, such as those used to treat endometriosis, which can cause amenorrhea; this type of amenorrhea is normal, and menstruation usually resumes after stopping the medication. Then there is pathological amenorrhea, typically seen with severe conditions like uterine endometrium or intrauterine adhesions, which can also cause a lack of menstruation. Additionally, ovarian secretory dysfunction, certain endocrine disorders, or premature ovarian failure, can all lead to amenorrhea, requiring related medical examinations and symptomatic treatment in a hospital.