It is mostly normal for girls to have delayed and irregular menstruation when they first get their periods. The main reason for this is that the ovarian function of girls is not yet particularly stable and the hormone level in the body is still in an unstable stage, which can lead to the shedding of the endometrium and irregular menstruation, which can cause irregular menstruation. If a girl is not well rested or under stress from studies, it may also affect her menstruation. As long as gynecological diseases are ruled out, there is no need for special treatment such as pubertal blood. It is recommended that girls develop good habits and ensure adequate nutrition, so that as they age and their ovaries continue to improve, their menstruation will become regular.