Aunt generally refers to menstruation, 12-year-old girls do not menstruate for a month is usually normal, parents do not need to be overly nervous. First of all, menstruation is a manifestation of the maturation of ovarian function in women. Most women have their first menstruation around the age of 12~15 years old, and some of them may advance or delay it for about 1 year, which is a normal situation. Secondly, even if a 12-year-old girl has had her first menstrual period and then does not menstruate for a month, this is also normal. Because the first menstruation only means that the ovaries are mature, but usually not yet fully developed, most girls may not menstruate again for several months after the first menstruation. At this time, parents do not need to be nervous, just keep observing. To summarize, it is usually normal for a 12-year-old girl not to menstruate for a month. However, if the interval between periods is too long, it is considered to be caused by insufficient estrogen levels in the body. Parents are advised to take the patient to the doctor for timely examination and, if necessary, to take estrogen supplements under the doctor’s guidance to help the patient establish a normal menstrual cycle.