It is normal for 12-year-old girls to have menstrual periods that are still irregular. Regular menstrual flow is a sign of female maturity, and most girls have their menstruation at the age of 13-14, commonly known as a period, but it is affected by the environment, nutrition, genetics, weight, etc. In recent years, many girls advance their menstruation to 10-12 years old. The early menstruation may be related to the environment, nutrition, food and other factors, although 12-year-old girls have their menstruation, but the positive feedback mechanism of estrogen is not mature, even if there is a mature follicle formation can not be normal ovulation, so the menstruation can not be very regular, this time lasts for about several years. After the first menstruation, girls should try not to eat cold and spicy food, and enhance balanced nutrition and care during menstruation. Develop good habits of regular work and rest, and as you grow older, your periods will gradually stabilize. In case of excessive menstruation and continuous bleeding during menstruation, you need to consult a doctor and take medication.