14-year-old menstruation, may be due to the following factors: First, genetic factors: If the mother is late to get menstruation, usually the daughter is also late to get menstruation. Secondly, dietary factors: If you are often picky or paranoid in your diet, malnutrition will lead to no menstruation at the age of 14. Third, disease factors: such as congenital hymenal atresia or congenital uterine dysplasia. If a girl is not menstruating after the age of 18, parents need to pay attention, should promptly take the child to the hospital for relevant examination to exclude pathological factors, if the pathological factors caused by not menstruating, you can carry out the corresponding treatment.